Federal Leadership Needed to Advance Research (GAO-22-104579)
Summary
A GAO report to congressional committees, GAO-22-104579, dated July 2022, on air travel and communicable diseases. It states that the COVID-19 pandemic intensified concerns about air travel's role in spreading disease and raised questions about the safety of aircraft passengers and crew. GAO identified research in several areas, for example on how air moves in aircraft and on the effect of airline operations such as boarding from back to front on the risk of disease exposure. Stakeholders GAO interviewed described the need for more research. Its title states that federal leadership is needed to advance research.
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United States Government Accountability Office
Report to Congressional Committees
July 2022
AIR TRAVEL AND
COMMUNICABLE
DISEASES
Federal Leadership
Needed to Advance
Research
Accessible Version
GAO-22-104579
July 2022
GAO Highlight AIR TRAVEL AND COMMUNICABLE DISEASES
Highlights of GAO-22-104579, a report to Federal Leadership Needed to Advance Research
congressional committees
Why GAO Did This Study What GAO Found
The COVID-19 pandemic has GAO identified research conducted on communicable diseases in air travel in
intensified ongoing concerns about air
several areas. For example, research has examined how air moves in aircraft
travel’s role in spreading disease and
raised questions about the safety of and studied the effect of different airline operations—such as boarding aircraft
passengers and crew. Research that from back to front—on the risk of disease exposure. However, stakeholders GAO
could provide quality information on interviewed described the need for more research involving real-world situations
communicable diseases in air travel and human behavior. Additional research could inform the development of
can help to protect public health. evidence-based mitigation measures, policy, and regulations to protect public
The CARES Act includes a provision health. Stakeholders cited several challenges, particularly the lack of federal
for GAO to monitor and report on leadership to facilitate interdisciplinary research and address gaps, to conducting
federal efforts related to the COVID-19 research on communicable diseases in air travel. Stakeholders said researchers’
pandemic. GAO was also asked to
review research on disease inability to access aircraft, airports, or data also poses challenges to performing
transmission in air travel. This report needed research.
examines: (1) the status of research on
Examples of Conditions or Behaviors That May Affect Disease Transmission on an Airplane
communicable diseases in air travel,
including stakeholders’ views on
additional needed research and
challenges to conducting it, and (2) the
extent to which FAA and other federal
agencies are advancing such research.
To conduct this work, GAO interviewed
stakeholders, including federal officials,
researchers, and aviation industry and
union representatives. GAO also
reviewed academic literature and Several agencies have focused on those research areas most relevant to their
agency documents, including research priorities and mission. Such agencies include the Department of Health and
plans, as well as key considerations for Human Services (HHS), the Department of Transportation’s Federal Aviation
interagency collaboration. Administration (FAA), and the Department of Homeland Security (DHS). None of
these agencies have undertaken efforts to advance needed research on
What GAO Recommends
communicable diseases in air travel more broadly. Officials with each of these
Congress should consider directing agencies said a more coordinated federal approach to identify and advance
FAA to develop and implement a relevant research could generate valuable information and inform policy
strategy to identify and advance development and guidance. In addition, bringing various federal agencies’ assets
needed research on communicable to bear could link researchers with aviation stakeholders across areas of
diseases in air travel, in coordination expertise, provide clearer access to federal funding for research, and help
with appropriate federal agencies— identify needed research across different disciplines.
such as DHS and HHS—and external
partners. While FAA acknowledges that it has broad authority to conduct and sponsor
research on communicable diseases in air travel, the agency has historically
maintained that this work lies outside its core responsibility for aviation safety.
Yet, FAA has prior experience conducting and supporting such research, as well
as strong aviation industry ties critical to advancing needed research. In
particular, FAA has undertaken related research in the past—usually in response
to statutory mandates—including work on disease transmission in aircraft cabins.
View GAO-22-104579. For more information, Moreover, leading the development of a coordinated strategy would be
contact Heather Krause at (202) 512-2834 or consistent with FAA’s efforts to develop a national aviation-preparedness plan, in
krauseh@gao.gov.
coordination with DHS and HHS, as GAO recommended. Such a strategy would
United States Government Accountability Office
help focus research efforts to better inform the development of policies and
requirements to protect the health of passengers and crew.
Contents
GAO Highlight 2
Why GAO Did This Study 2
What GAO Recommends 2
What GAO Found 2
Letter 1
Background 4
Stakeholders Identified Additional Research Needed on
Communicable Diseases in Air Travel and Challenges to
Conducting It 12
Absence of Federal Leadership Has Hindered the Advancement
of Research on Communicable Diseases in Air Travel 20
Conclusions 26
Matter for Congressional Consideration 27
Agency Comments 27
Appendix I: Objectives, Scope, and Methodology 31
Appendix II: Selected Research on Communicable Diseases in Air Travel 36
Appendix III: FAA Health and Safety Research Mandated by Statute 39
Appendix IV: GAO Contact and Staff Acknowledgments 40
Tables
Table 1: Agency Research Priorities Related to Communicable
Diseases in Air Travel 10
Table 2: Examples of Federal Assets and Expertise for Advancing
Research on Communicable Diseases in Air Travel 21
Table 3: Researchers Interviewed to Solicit Views on
Communicable Diseases in Air Travel 32
Table 4: Additional Aviation Stakeholders Interviewed 33
Table 5: Key Features of Effective Interagency Collaboration 35
Table 6: Selected References for Research Areas Related to
Communicable Diseases in Air Travel 36
Figures
Figure 1: Example of Airport Covid-19 Mitigation 7
Page i GAO-22-104579 Air Travel and Communicable Diseases
Figure 2: Selected Research Areas for Communicable Diseases in
Air Travel and Examples of Research 13
Figure 3: Examples of Conditions or Behaviors on an Airplane
That May Affect Disease Transmission 17
Figure 4: CDC Guidelines for Potential Exposure to
Communicable Diseases in Flight 18
Figure 5: Federal Aviation Administration’s (FAA) Responses to
Statutory Mandates for Research on Cabin Air Quality
and Health Effects (1994 through 2020) 39
Page ii GAO-22-104579 Air Travel and Communicable Diseases
Abbreviations
ACER National Center of Excellence for Airliner Cabin
Environment Research
ACERite National Air Transportation Center of Excellence for
Research in the Intermodal Transport Environment
AMC Air Mobility Command
CAMI Civil Aerospace Medical Institute
DHS Department of Homeland Security
DOT Department of Transportation
CDC Centers for Disease Control and Prevention
DGMQ Division of Global Migration and Quarantine
FAA Federal Aviation Administration
HEPA high efficiency particulate air
HHS Department of Health and Human Services
MERS Middle East Respiratory Syndrome
MOU memorandum of understanding
NASA National Aeronautics and Space Administration
NIAID National Institute of Allergy and Infectious Diseases
NIOSH National Institute for Occupational Safety and Health
OSHA Occupational Safety and Health Administration
R&D research and development
REDAC Research, Engineering, and Development Advisory
Committee
S&T Science and Technology Directorate
SARS severe acute respiratory syndrome
TRANSCOM U.S. Transportation Command
TSA Transportation Security Administration
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Page iii GAO-22-104579 Air Travel and Communicable Diseases
441 G St. N.W.
Washington, DC 20548
Letter
July 28, 2022
Congressional Committees
As of June 2022, nearly 85 million cases of COVID-19 had been reported
in the United States, resulting in over a million deaths.1 COVID-19 is only
the latest disease to raise concerns about communicable diseases in air
travel, including both health risks to passengers and the unique role that
air travel plays in the spread of diseases globally.2 Since 2002, several
major public health epidemic threats have had global ramifications,
including the severe acute respiratory syndrome (SARS) in 2003, the
H1N1 influenza pandemic in 2009, the Middle East Respiratory Syndrome
(MERS) in 2012, and Ebola in 2014.
These disease outbreaks have led to calls for the Department of
Transportation (DOT) and the Federal Aviation Administration (FAA), in
cooperation with other relevant federal agencies, to be more involved in
preparing for and responding to the threat posed by communicable
diseases in air travel. Throughout the COVID-19 pandemic, discussion
has continued over governmental policies and requirements addressing
travel restrictions, masking, testing, vaccinations, aircraft occupancy
restrictions, and the ventilation of aircraft, among other areas affecting
both air travel and public health. While research could improve the quality
of information used to inform the development of such policies and
requirements, we have previously reported that FAA has sponsored
1Data on COVID-19 cases in the U.S. are based on aggregate case reporting to the
Centers for Disease Control and Prevention (CDC) and include probable and confirmed
cases as reported by states and jurisdictions. CDC COVID-19 counts are subject to
change due to delays or updates in reported data from states and jurisdictions. According
to CDC, the actual number of COVID-19 cases is unknown for a variety of reasons,
including that people who have been infected may have not been tested or may have not
sought medical care. See CDC, “COVID Data Tracker: Trends in Number of COVID-19
Cases and Deaths in the US reported to CDC, by State/Territory,” accessed June 7, 2022,
https://covid.cdc.gov/covid-data-tracker/#trends_dailycases.
2For more information, see GAO, Air Travel and Communicable Diseases:
Comprehensive Federal Plan Needed for U.S. Aviation System’s Preparedness,
GAO-16-127 (Washington, D.C.: Dec. 16, 2015).
Page 1 GAO-22-104579 Air Travel and Communicable Diseases
Letter
limited federal research into disease transmission onboard aircraft and in
airports.3
The CARES Act includes a provision for us to report on our ongoing
monitoring and oversight efforts related to the COVID-19 pandemic.4 This
report is a part of that body of work. We were also asked to review the
status of research on disease transmission via air travel. This report
examines:
· the status of research on communicable diseases in air travel,
including stakeholders’ views on additional needed research and the
challenges to conducting it, and
· the extent to which FAA and other federal agencies are advancing
such research.
For the purposes of our review, air travel refers to the movement of
passengers and crew through airports, onto and off aircraft, and in flight.
Our scope does not include air travel’s role in facilitating the spread of
diseases from one part of the world to another, or between different
modes of transportation (e.g., airport to bus or transit system).
To examine the status of research on communicable diseases in air travel
and challenges to conducting this research, we reviewed academic
literature and prior GAO work, monitored relevant news and publications,
and interviewed researchers and other stakeholders. Our
nongeneralizable selection of stakeholders included researchers, union
and industry representatives, and federal agency officials. We identified
3In June 2020, we testified to Congress regarding the status of FAA’s research efforts. For
more information, see GAO, Air Travel and Communicable Diseases: Status of Research
Efforts and Action Still Needed to Develop Federal Preparedness Plan, GAO-20-655T
(Washington, D.C.: June 23, 2020). For more information about how quality information is
needed for federal management, see GAO, Standards for Internal Control in the Federal
Government, GAO-14-704G (Washington, D.C.: Sept. 10, 2014).
4Pub. L. No. 116-136, § 19010(b), 134 Stat. 281, 579-80 (2020). We regularly issue
government-wide reports on the federal response to COVID-19. For the latest report, see
GAO, COVID-19: Current and Future Federal Preparedness Requires Fixes to Improve
Health Data and Address Improper Payments, GAO-22-105397 (Washington, D.C.: Apr.
27, 2022).
Page 2 GAO-22-104579 Air Travel and Communicable Diseases
Letter
these stakeholders to interview through open-source research, our
literature search, and through interviews.5
We conducted interviews with 17 researchers across seven issue areas,
including ventilation and filtration, human behavior, and epidemiology.6 In
addition to researchers, we interviewed representatives from unions for
flight attendants and pilots, as well as consumer advocates. We also
gathered aviation industry views from Airlines for America, Airports
Council International North America, and Delta Air Lines. We spoke to
federal agency officials at the FAA Office of Aerospace Medicine’s Civil
Aerospace Medical Institute (CAMI), the Centers for Disease Control and
Prevention’s (CDC) National Institute for Occupational Safety and Health
(NIOSH), and the Department of Homeland Security’s (DHS) Science and
Technology Directorate, among others.
To examine the extent to which FAA and other federal agencies are
advancing research on communicable diseases in air travel, we reviewed
agency reports and documents, including research plans for FAA and
selected agencies within DHS and the Department of Health and Human
Services (HHS). In this context, advancing research would include
providing sustained support to identify and further needed research. We
also interviewed officials from the agencies noted above, as well as
officials with CDC’s Division of Global Migration and Quarantine and
DHS’s Transportation Security Administration (TSA). We identified these
agencies based on our initial meeting with FAA and internal discussions
with GAO stakeholders.
In addition, we have identified federal collaborative efforts for research in
our prior work, including a review assessing FAA’s collaboration with
5Our initial literature review identified peer-reviewed studies published in 2020 and
included work conducted in a variety of research areas. For the purposes of this report, we
have focused our findings on those research areas that are most salient to COVID-19. To
better understand how the volume of research published on communicable diseases in air
travel has changed over time, we performed two additional citation-count searches in
Scopus, for academic journal articles and conference papers published from January
2011 through July 2021. We continued to monitor research publications through March
2022 and contacted researchers and agency officials to stay abreast of relevant research.
See appendix I for more information about our literature review. See appendix II for
additional information about research on communicable diseases in air travel, including
selected citations.
6More information about these issue areas and researchers is included in appendix I.
Page 3 GAO-22-104579 Air Travel and Communicable Diseases
Letter
NASA.7 We reviewed key considerations for interagency collaboration to
identify mechanisms and associated leading practices for effective
collaboration, which is defined broadly as any joint activity that is intended
to produce more public value than could be produced when agencies act
alone.8 See appendix I for additional detail on our scope and
methodology.
We conducted this performance audit from October 2020 to July 2022 in
accordance with generally accepted government auditing standards.
Those standards require that we plan and perform the audit to obtain
sufficient, appropriate evidence to provide a reasonable basis for our
findings and conclusions based on our audit objectives. We believe that
the evidence obtained provides a reasonable basis for our findings and
conclusions based on our audit objectives.
Background
Communicable Diseases in Air Travel
Air travel is unique with regard to the transmission of communicable
disease, among travelers and in communities.9 A 2013 report prepared by
7GAO, Aviation Research and Development: FAA Could Improve How It Develops Its
Portfolio and Reports Its Activities, GAO-17-372 (Washington, D.C.: Apr. 24, 2017).
8For more information about collaborative mechanisms and associated leading practices,
see GAO, Managing for Results: Key Considerations for Implementing Interagency
Collaborative Mechanisms, GAO-12-1022 (Washington, D.C.: Sept. 27, 2012). For the
purposes of a collaborative strategy for research on communicable diseases in air travel,
relevant features include identifying leadership, clarifying roles and responsibilities,
determining resources needed, and documenting relevant agreements. More information
about these practices is provided in appendix I.
9While outside the scope of our work, a 2021 study found a strong relationship between
cases of COVID-19 and air passenger volume, using real flight data to measure air
travel’s impact on the COVID-19 pandemic. For more information, see Lu Dai, Ivan
Tereshchenko, Mark Hansen, “Quantifying the Impact of Air Travel on Growth of COVID-
19 Pandemic in the United States,” presented at the Fourteenth USA/Europe Air Traffic
Management Research and Development Seminar (ATM2021).
Page 4 GAO-22-104579 Air Travel and Communicable Diseases
Letter
the Airport Cooperative Research Council identified transmission risks
specific to air travel, including:10
· Aircraft cabin. Within the aircraft cabin, passengers and crew from
different geographic regions can be in close proximity for long
durations with limited cleaning between uses through any given day.
Opportunities for disease transmission may occur not only while
directly adjacent to an infectious person during flight, but also during
boarding or disembarking as the passenger traverses a contaminated
area or touches a contaminated surface. Aircraft ventilation systems—
particularly high efficiency particulate air (HEPA) systems—can
mitigate some of these risks, if they are in operation.11
· Airports. Airports differ from other settings such as schools, malls,
and movie theaters in the scale and nature of interactions. At airports,
a large number of individuals from geographically diverse regions with
differing population immunity and endemic diseases all interact with
airline and airport operations staff and with each other.12
· Transmission routes. There are three general routes of transmission
for communicable diseases in air travel: (1) through aerosols that
remain airborne for long periods and can be inhaled, (2) through large
droplets that may be ingested or settle on surfaces, or (3) through
direct contact with secretions, bodily fluids, or contaminated
surfaces.13
10This report, which focused on the mitigation of infectious disease in airports and on
aircraft, was prepared by the Airport Cooperative Research Council (ACRP) of the
Transportation Research Board with support from FAA. For more information, see
National Academies of Sciences, Engineering, and Medicine, Infectious Disease
Mitigation in Airports and on Aircraft, https://doi.org/10.17226/22512 (Washington, D.C.:
2013).
11HEPA filtration can remove 99.9 percent of virus and bacteria particulates and exchange
cabin air every 2 to 3 minutes, according to Boeing, which provides information about
aircraft ventilation on its website. See Boeing, “Travel Confidently with Boeing: Cabin Air,”
accessed January 21, 2022, https://www.boeing.com/confident-travel/cabin-air.html. Not
all aircraft have HEPA filtration.
12In statute and regulation, airlines are generally referred to as “air carriers”; we refer to
them as “airlines” for the purposes of this report.
13Some infectious diseases are contagious (or communicable), that is, spread from one
person to another. Other infectious diseases can be spread by germs carried in air, water,
food, or soil. They can also be spread by vectors (like biting insects) or by animals. For
purposes of this report, we are focused on those communicable diseases that might be
spread from person to person during travel.
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Letter
During the COVID-19 pandemic, understanding of how the disease is
transmitted has improved, yet some basic information remains unknown
or has changed as the virus continues to evolve and new variants
emerge.14 For example, SARS-CoV-2, the novel coronavirus that causes
COVID-19, is now known to spread when an infected person breathes out
droplets or aerosols, which may be inhaled or spread through contact with
the eyes, nose, or mouth. The infectiousness of the virus has changed
over time with the emergence of variants, such as Delta and Omicron.
Moreover, vaccine effectiveness can vary in protecting individuals against
different variants.15 Questions about the risk factors associated with the
transmission of COVID-19 also remain.
Throughout the COVID-19 pandemic, airports and airlines have taken
different approaches to protecting passengers.16 For example, some
airlines independently added additional cleaning protocols for their
aircraft, kept middle seats empty, or required masking prior to the federal
mandates. Mitigation practices differed in other areas as well, such as
whether airlines operated aircraft ventilation systems during boarding and
deplaning, as has been recommended by the Airport Cooperative
Research Program and others to improve cabin air quality and reduce the
spread of pathogens. Individual airports also took steps including
changes in their cleaning regimes or calling for social distancing to
minimize the spread of the virus.17 (See fig. 1.)
14For example, the infectivity and infectiousness of SARS-CoV-2 is not fully known and
may likely vary by individual. Infectivity is the ability of the disease agent to enter, survive,
and multiply in the host. Infectiousness indicates the relative ease with which a disease is
transmitted to other hosts. Officials with DHS also pointed to the need for additional
research on basic characteristics of the virus, as well as the number and size of particles
emitted by infected people during routine activities such as coughing, breathing, and
speaking.
15For more information about Coronavirus variants, see Kathy Katella, “Omicron, Delta,
Alpha, and More: What to Know about the Coronavirus Variants,” Yale Medicine,
accessed February 28, 2022, https://www.yalemedicine.org/news/covid-19-variants-of-
concern-omicron.
16During the COVID-19 pandemic, CDC issued some orders, such as those limiting entry
for certain persons, testing requirements for those boarding a flight to the United States
and vaccination requirements for noncitizens who are non-immigrants seeking to enter the
United States by air travel. As of July 2022, some of these orders have been extended,
amended, replaced, terminated, or vacated by a federal district court.
17Because airports are often owned by state, local, territorial, tribal, or multi-jurisdictional
public entities, mitigations may vary by locality.
Page 6 GAO-22-104579 Air Travel and Communicable Diseases
Letter
Figure 1: Example of Airport Covid-19 Mitigation
As understanding of COVID-19 has evolved, federal, state, and local
policies and responses also have changed. For example, initial guidance
on COVID-19 from CDC and others focused on addressing the risk from
contaminated surfaces and droplet transmission. Attention later turned to
mitigating the spread of aerosols, when it became clearer that COVID-19
is primarily an airborne, respiratory disease. In response, persons in U.S.
airports had, up until April 18, 2022, been subject to federal mask
mandates, as discussed below.18
18This applied to persons in airports subject to the jurisdiction of the United States. On
April 18, 2022, a federal district court order vacated the CDC’s mask mandate, finding that
the CDC’s mask mandate exceeds CDC’s statutory authority and violates the procedures
required for agency rulemaking under the Administrative Procedure Act. The case was
remanded to the CDC for further proceedings consistent with the judicial order, Health
Freedom Defense Fund, Inc., et al v. Biden et al, 8:21-cv-1693-KKM-AEP (April 18, 2022).
On April 20, 2022, the Department of Justice filed a notice of appeal of the federal district
court order.
Page 7 GAO-22-104579 Air Travel and Communicable Diseases
Letter
Federal Roles and Research Priorities
A number of federal agencies have roles and responsibilities in preparing
for communicable disease threats in the aviation system, assessing them,
and responding to them. The missions and legal authorities of the
agencies in our review guide these roles and responsibilities.19 HHS and
DHS focus on protecting the nation from domestic and foreign health,
safety, and security threats and protecting our borders at ports of entry,
including airports, from threats from abroad.20 Within DOT, FAA is
generally responsible for aviation safety. More specifically:
· Within HHS, CDC aims to protect the nation’s health—together with
local health departments—and generally addresses disease
surveillance and infection control. Within CDC, the Division of Global
Migration and Quarantine focuses on the public health risks of rapid
global travel, because diseases and outbreaks can quickly cross
international borders. Also within CDC, NIOSH studies occupational
safety and health.
19Although not included in our review, the Occupational Safety and Health Administration
(OSHA) within the Department of Labor aims to assure safe and healthful conditions for
workers by setting and enforcing standards and by providing training, outreach, education,
compliance, and assistance. OSHA standards are not applicable to working conditions for
aircraft cabin crewmembers onboard an aircraft while it is in operation, with the exception
of OSHA’s standards on hazard communication, blood-borne pathogens exposure, and
occupational noise exposure, as recognized in a memorandum of understanding (MOU)
between OSHA and FAA. An aircraft is considered by FAA to be “in operation” from the
time it is first boarded by a crewmember, in preparation for a flight, to the time the last
crewmember leaves the aircraft after completion of that flight. See Memorandum Of
Understanding Between The Federal Aviation Administration U.S. Department Of
Transportation And The Occupational Safety And Health Administration U.S. Department
Of Labor, August 26, 2014.
20Under section 361 of the Public Health Service Act, as amended (codified as amended
at 42 U.S.C. § 264), HHS is authorized to make and enforce regulations to prevent the
introduction, transmission, or spread of communicable diseases from foreign countries
into the United States or possessions and among states and possessions. The authority
for carrying out these functions on a daily basis has been delegated to CDC, an agency in
HHS. With respect to DHS, the National Defense Authorization Act for Fiscal Year 2022,
enacted in December 2021, requires the Secretary of DHS, acting through TSA, in
coordination with the Chief Medical Officer of DHS, and in consultation with appropriate
federal departments and agencies, including HHS, CDC, DOT, the Department of Labor,
appropriate interagency task forces, and certain specified types of public and private
stakeholders, to develop a transportation security preparedness plan to address the event
of a communicable disease outbreak. Pub. L. No. 117-81, § 6412, 135 Stat. 1541, 2409
(2021).
Page 8 GAO-22-104579 Air Travel and Communicable Diseases
Letter
· Within DHS, Customs and Border Patrol aims to safeguard the
nation’s borders and TSA is responsible for securing the nation’s
transportation system. During the COVID-19 pandemic, for example,
TSA issued several security directives to address COVID-19 in travel
and to implement a federal executive order mask mandate and
enforce a related CDC order.21
· Within DOT, FAA and the Office of the Secretary of Transportation are
generally responsible for aviation safety and for aviation economic
matters and consumer protection, respectively. In these roles, FAA
and DOT’s Office of the Secretary have promulgated rules addressing
public safety and health issues, such as the use of seatbelts and
smoking aboard U.S.-regulated aircraft. DOT and FAA have strong
ties to key aviation stakeholders, such as international civil aviation
organizations. They also have oversight responsibilities for airlines,
airports, and other members of the aviation industry. For example, in
response to COVID-19, FAA and DOT’s Office of the Secretary
collaborated with interagency partners on the development of
international and domestic guidance for airlines, airports, and others
to mitigate the public health risks of COVID-19.22 To help improve the
U.S. aviation sector’s preparedness for future communicable disease
threats, DOT has recently agreed to work closely with DHS and HHS
to develop a national aviation-preparedness plan, in accordance with
international standards and as we have recommended since 2015.23
21During the COVID-19 pandemic, TSA has issued various security directives, among
other things, to implement Executive Order 13998, Promoting COVID-19 Safety in
Domestic and International Travel, and CDC’s related Order, Requirement for Persons to
Wear Masks While on Conveyances and at Transportation Hubs. Executive Order 13998,
86 Fed. Reg. 7205 (Jan. 26, 2021); CDC, Requirement for Persons to Wear Masks While
on Conveyances and at Transportation Hubs, 86 Fed. Reg. 8025 (Feb. 3, 2021). TSA
security directives include, for example, Transportation Security Administration, Mask
Requirements for Airports within the United States, SD 1542-21-01C (Dec. 17, 2021);
Transportation Security Administration, Mask Requirements for Aircraft Operators
Regulated under 49 C.F.R. 15444.101, SD 1544-21-02C (Dec. 17, 2021).
22For example, in December 2020, DOT, DHS, and HHS jointly issued updated guidance
to airports and airlines for implementing measures to mitigate the public health risks
associated with COVID-19. See Runway to Recovery: The United States Framework for
Airlines and Airports to Mitigate the Public Health Risks of Coronavirus, Version 1.1,
Guidance Jointly Issued by the U.S. Departments of Transportation, Homeland Security,
and Health and Human Services (Washington, D.C.: December 2020).
23For more information, see GAO, Air Travel and Communicable Diseases:
Comprehensive Federal Plan Needed for U.S. Aviation System’s Preparedness,
GAO-16-127 (Washington, D.C.: Dec. 16, 2015), and GAO, Covid-19: Opportunities to
Improve Federal Response and Recovery Efforts, GAO-20-625 (Washington, D.C.: June
25, 2020).
Page 9 GAO-22-104579 Air Travel and Communicable Diseases
Letter
Each agency also supports research as related to its mission, as shown
in table 1.
Table 1: Agency Research Priorities Related to Communicable Diseases in Air Travel
Selected Agency Research Priorities
CDC’s National Institute for NIOSH’s mission is to develop new knowledge in the field of occupational safety and health and
Occupational Safety and Health to transfer that knowledge into practice. NIOSH research priorities cross worker populations and
(NIOSH) sectors, such as agriculture and transportation, and include workers in air travel settings.
CDC’s Division of Global Migration DGMQ has a public health response role that is supported through public health surveillance,
and Quarantine (DGMQ) contact tracing, and outbreak investigations related to the aviation sector. While it does not
have a formal research role, according to officials, the findings of its investigations may
contribute to research by others.
DHS’s Science and Technology S&T conducts basic and applied research, development, testing, and evaluation activities. It
Directorate (S&T) coordinates its R&D strategy with other branches of DHS, including the Transportation Security
Administration. Research priorities have traditionally been focused on improving security—
including improvement within the nation’s transportation systems, such as checkpoint
automation.
Federal Aviation Administration FAA’s research priorities are focused on commercial and general aviation flight safety. These
(FAA) priorities are guided by five goals: improving operations, accelerating the use of new
technologies, capitalizing infrastructure, improving the operation of the human component of the
system, and improving modeling capabilities and analysis.
Source: GAO analysis of information from the Centers for Disease Control and Prevention (CDC), the Department of Homeland Security (DHS), and the Federal Aviation Administration (FAA). │
GAO-22-104579
FAA supports and coordinates a range of research activities for the civil
aviation system—both through in-house research and in collaboration
with other entities.24 Support for external research can include conducting
research with or making grants to other government agencies,
universities, and private sector organizations.25 Within the agency,
research is conducted primarily by the:
24According to FAA officials, in addition to specific statutory mandates, the FAA relies
primarily on statutory authorities in 49 U.S.C. Chapter 445 to conduct a wide range of
aviation safety-related research and development. For example, pursuant to 49 U.S.C. §
44513, the FAA may make grants to institutions of higher education that are members of
FAA regional centers of air transportation excellence for “aviation safety and security” and
“other aviation issues related to developing and maintaining a safe and efficient air
transportation system.” 49 U.S.C. § 44513(b)(1)(A)(iv), (vi).
25For example, under 49 U.S.C. Chapter 445, FAA is to, among other things, conduct or
supervise research on aviation safety and “other aviation issues related to developing and
maintaining a safe and efficient air transportation system” (49 U.S.C. § 44505(c)), and
may enter into cooperative agreements with federal and non-federal entities to conduct,
encourage, and promote aviation research, engineering, and development, including the
development of prototypes and demonstration models (49 U.S.C. § 44505(e)), and may
make grants to institutions of higher education and nonprofit research organizations to
conduct aviation research in areas the Administrator considers necessary for the long-
term growth of civil aviation (49 U.S.C. § 44511(a)).
Page 10 GAO-22-104579 Air Travel and Communicable Diseases
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· Office of Aerospace Medicine and the Civil Aerospace Medical
Institute (CAMI). To enhance aviation safety, CAMI focuses on
people in the aviation system (e.g., pilots, flight attendants,
passengers, and air traffic controllers) by applying known science to
improve aerospace operations and to avoid aircraft accidents and
incidents.
· William J. Hughes Technical Center. FAA also carries out research
at its William J. Hughes Technical Center, where engineers,
scientists, mathematicians, and technical experts work to modernize
and sustain the National Aviation System, which includes the nation’s
air-traffic control facilities.
FAA’s National Aviation Research Plan documents the agency’s research
goals, objectives, and outputs. This plan is developed through a process
involving both internal FAA stakeholders and aviation industry
stakeholders (the agency’s Research, Engineering, and Development
Advisory Committee); it is organized by the agency’s research goals.26
26In 2017, we found that FAA’s actions related to the management of its research and
development (R&D) portfolio were not fully consistent with statutory requirements, agency
guidance, and leading practices. Accordingly, we recommended that DOT direct FAA to
(1) take a more strategic approach to identifying long-term R&D research priorities across
the agency, (2) disclose how research projects are prioritized and selected, and (3) ensure
that FAA’s National Aviation Research Plan and R&D annual reviews meet statutory
requirements for content. DOT agreed with and has subsequently implemented all three of
these recommendations. For more information, see GAO-17-372.
Page 11 GAO-22-104579 Air Travel and Communicable Diseases
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Stakeholders Identified Additional Research
Needed on Communicable Diseases in Air
Travel and Challenges to Conducting It
Existing Research Spans Several Areas
Research on communicable diseases in air travel spans several areas,
such as ventilation and filtration, human behavior, and operations.27
Figure 2 provides examples of this research, including work to assess the
effects of layered mitigations to reduce disease transmission in air travel.
While researchers have paid additional attention to the risk of
communicable diseases in air travel during the pandemic, a portion of this
work predates COVID-19. Some of this research—including studies on
aircraft cabin ventilation and operations—was based on modeling. For
example, researchers used computer, chemical, or biological models to
simulate various scenarios in which communicable diseases could be
transmitted in air travel.28 For more information about research on
communicable diseases in air travel, see appendix II.
27We identified relevant research through interviews with researchers and other
stakeholders, as well as our review of academic literature, relevant news and publications,
and our prior work. Our initial literature review identified peer-reviewed studies published
in 2020 and included work conducted in a variety of research areas. For the purposes of
this report, we have focused our findings on those research areas that are most salient to
COVID-19. To better understand how the volume of research published on communicable
diseases in air travel has changed over time, we performed two additional citation-count
searches in Scopus, for academic journal articles and conference papers published from
January 2011 through July 2021. We continued to monitor research publications through
March 2022 and contacted researchers and agency officials to stay abreast of relevant
research. See appendix I for more information about our literature review. See appendix II
for additional information about research on communicable diseases in air travel, including
selected citations. The research we identified does not include all research conducted on
communicable diseases in air travel.
28For an example of research using computer modeling, see R. John Milne, Camelia
Delcea, and Liviu-Adrian Cotfas, “Airplane Boarding Methods that Reduce Risk from
COVID-19,” Safety Science 134, (2021). For an example of chemical modeling, see
TRANSCOM/AMC Commercial Aircraft Cabin Aerosol Dispersion Tests, submitted to U.S.
Transportation Command (TRANSCOM) and Air Mobility Command (AMC) (Oct. 15,
2020), which used tracer gases. For an example of a study using biological modeling
techniques, see Watts L. Dietrich, James S. Bennett, Byron W. Jones, and Mohammad H.
Hosni, “Laboratory Modeling of SARS-CoV-2 Exposure Reduction through Physically
Distanced Seating in Aircraft Cabins using Bacteriophage Aerosol - November 2020,”
MMWR - Morbidity and Mortality Weekly Report 70, no. 16 (Apr. 23, 2021): 595-599,
which used bacteriophages.
Page 12 GAO-22-104579 Air Travel and Communicable Diseases
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Figure 2: Selected Research Areas for Communicable Diseases in Air Travel and
Examples of Research
Note: These areas were selected because they are relevant to COVID-19. For example, we did not
include examples of research on surface cleaning and disinfection.
The real-world applicability of models is limited by assumptions they
employ and the amount and quality of data needed to validate them,
among other things. In some cases, researchers substituted known
parameters as proxies for unknown ones, such as when researchers
used the infectiousness of other diseases as a proxy for that of COVID-
19. In another instance, researchers used a mannequin to stand in for
passengers in a mock aircraft cabin to study the dispersion of aerosols
and made other assumptions given the unknowns about the disease.
Page 13 GAO-22-104579 Air Travel and Communicable Diseases
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Results from this study on the potential time needed for disease
transmission are hypothetical, according to the authors of the study.29
While much of the research we identified was conducted by researchers
affiliated with universities or industry, a small proportion of the studies we
identified on communicable diseases in air travel was sponsored or
conducted by a federal partner.30 In interviews, officials with CDC’s
NIOSH, DHS’s Science and Technology Directorate, and FAA each
provided examples of research conducted during the COVID-19
pandemic with varying relevance to disease transmission in air travel.
These examples included:
· CDC’s NIOSH, which focuses on occupational safety and health,
conducted a study on the relative risk reduction of blocking middle
seats. NIOSH researchers collaborated with academic researchers on
this work, including an academic who had previously worked with FAA
through a cabin air-quality research program that has now been
discontinued, as is discussed later in this report.31
· DHS’s Science and Technology Directorate performed various
research on behalf of TSA, including modeling that may have
relevance to disease transmission. This effort leveraged existing work
29TRANSCOM/AMC (2020). The authors of this study, conducted with sponsorship from
United Airlines and Boeing, published a revised cover sheet for the study, which noted,
“The authors of this study are concerned about the potential misinterpretation of the
findings, based on some hypothetical calculations originally included as discussion points.
In particular, the viral aerosol production rates, infectious dose and general assumptions
used to estimate a flight time of 54 hours to produce an infection are hypothetical and
were not designed to provide actionable information about viral risk during flight, safe flight
times or seating capacity.”
30In our initial literature review, for example, we identified eight studies that had a federal
partner or sponsor, out of 66 studies, including one sponsored by the Center for Advanced
Transportation Mobility and DOT. See Derjany, P., S. Namilae, D. Liu, and A. Srinivasan,
“Multiscale Model for the Optimal Design of Pedestrian Queues to Mitigate Infectious
Disease Spread,” Plos One 15, no. 7 (2020). Other federal agencies sponsoring or
partnering in research included National Science Foundation, CDC, HHS, the Veterans
Administration, and the Department of Defense, including TRANSCOM. “Partnering” may
simply mean that one of the coauthors on a study was affiliated with a federal agency. In
addition, during our interviews, researchers at TSA described work that they had done in
collaboration with the Environmental Protection Agency regarding disinfectants. For more
information on our literature searches, see appendix I.
31Watts L. Dietrich, et al., “Laboratory Modeling of SARS-CoV-2 Exposure Reduction
through Physically Distanced Seating in Aircraft Cabins using Bacteriophage Aerosol -
November 2020,” MMWR - Morbidity and Mortality Weekly Report 70, no. 16 (Apr. 23,
2021): 595-599.
Page 14 GAO-22-104579 Air Travel and Communicable Diseases
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intended to evaluate chemical terrorism to assess airflow onboard
aircraft. In addition, the Directorate performed applied research in five
areas related to TSA’s operational needs at security checkpoints—
ultraviolet disinfection of security bins, use of dogs to detect COVID-
19, face coverings for TSA personnel, reuse of explosive trace
detection swabs, and cleaning solutions.32 The Directorate has also
conducted additional work; some of which has been published in
peer-reviewed journals and is posted on the agency’s website.33
· In response to the COVID-19 pandemic, FAA has studied risks posed
by carrying large quantities of dry ice needed for the transport of
COVID-19 vaccines, as well as the effect of increased disinfectant use
on aircraft materials. These efforts focus on safety questions related
to the aircraft but do not include an assessment of the disease
infection risk to the aircraft’s occupants. In addition, FAA researchers
within the agency’s Office of Aerospace Medicine told us they were
developing a general model for communicable disease transmission
in aircraft cabins based on existing disease transmission models.
According to FAA officials, this modeling work was initiated in
response to GAO testimony and draft fiscal year 2021 House
appropriations committee language.34
Prior to the COVID-19 pandemic, FAA supported research on the air
cabin environment. Specifically, that work was performed from 2004
through 2014 under the aegis of the National Center of Excellence for
Airliner Cabin Environment Research (ACER), which was established by
FAA’s former Office of Regulation and Certification in response to
congressional actions, as described below.35 ACER brought together
airliner cabin environment expertise from academic, industry, and
government organizations and published reports addressing disease
transmission in airliner cabins, the health effects of aircraft cabin pressure
32For more information, see GAO, COVID-19: TSA Could Better Monitor Its Efforts to
Reduce Infectious Disease Spread at Checkpoints, GAO-21-364 (Washington, D.C.: June
14, 2021).
33For more information including links to peer-reviewed articles, see DHS, “Probabilistic
Analysis for National Threats Hazards and Risks (PANTHR),” accessed January 20, 2022,
https://www.dhs.gov/science-and-technology/panthr.
34See GAO-20-655T. Several laws have required FAA to study cabin air quality and
associated health effects. Besides work conducted in response to such statutory
mandates and its recently initiated modeling work in response to COVID-19, FAA has not
independently pursued research on communicable diseases in air travel since 2003.
Appendix III describes a selection of these laws and research since 1994.
35In 2007, the ACER was broadened and renamed the National Air Transportation Center
of Excellence for Research in the Intermodal Transport Environment (ACERite).
Page 15 GAO-22-104579 Air Travel and Communicable Diseases
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in older and vulnerable passengers, and decontamination technologies
for use on narrow-body and wide-body aircraft, among other topics.
Stakeholders Said More RealWorld Research Is Needed
to Better Protect Passengers and Crew
All of the researchers we spoke with identified additional research on
communicable diseases in air travel—especially involving real-world
situations and human behavior—that is still needed to better understand
transmission risks. This additional research could help address limitations
in the models used in some research conducted thus far and inform
practices and policies that could better protect passengers and crew
members.36
Researchers in various fields described to us the need for more research
spanning various disciplines that involves real-world situations and
human behavior aboard aircraft and in airports (see fig. 3). For example,
in the area of ventilation and filtration, researchers pointed to the need for
more work characterizing airflow in aircraft, including when passengers
use adjustable vents above their seats, and in airport locations with
crowds, such as at security checkpoints or in boarding areas. Infectious
disease researchers, in particular, said that more research to identify
where transmission occurred in specific cases (i.e., in-flight or elsewhere
in the travel journey) would be beneficial.37
36Our review identified only one real-world study on COVID-19 and commercial flights that
included passengers prior to flight—in contrast to epidemiological studies performed after
the fact to document cases of potential disease transmission. This study, conducted by
Delta Air Lines in coordination with academic researchers, looked at the effectiveness of
testing passengers 72 hours prior to departure. See Aaron J. Tande, et al., “SARS-CoV-2
Testing Prior to International Airline Travel, December 2020-May 2021,” Mayo Clinic
Proceedings (November 2021). For more information on airlines’ testing and tracing
practices, see GAO, Contact Tracing for Air Travel: CDC’s Data System Needs
Substantial Improvement, GAO-22-105018 (Washington, D.C., July 11, 2022).
37DHS officials added that research is also needed on inflight airflow, filter efficiency as a
function of aircraft age, and any impact on airflow when adjusting the ratio of fresh to
recycled air.
Page 16 GAO-22-104579 Air Travel and Communicable Diseases
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Figure 3: Examples of Conditions or Behaviors on an Airplane That May Affect Disease Transmission
A better understanding of the transmission of COVID-19 and other
diseases in real-world air travel situations could help researchers improve
their models and could lead to safer practices. For example, once the
infectious doses and transmission modes of SARS-CoV-2 and other
diseases are better understood, infectious diseases experts could help
operations researchers improve their models. Operations researchers
studying how passengers board aircraft—such as boarding aircraft from
back to front—could then replace the proxies used to develop models
with empirical data.
Stakeholders—including a travel medicine researcher, an epidemiologist
who studies respiratory diseases, and representatives from the flight
attendants union with expertise in industrial hygiene and occupational
safety and health—also told us that research to better inform policies that
affect flight and cabin crews would be beneficial because of their potential
exposure to communicable diseases while on the job. Specifically,
representatives for the Association of Flight Attendants advocated for
additional research on disease exposure onboard an aircraft. They raised
concerns that current guidelines may put the health and safety of flight
attendants and passengers at risk, with implications for quarantine and
work-time requirements.38 For example, current guidelines define disease
exposure as being within 6 feet of an infected individual for at least 15
minutes. These representatives told us that flight attendants’ actions—
such as moving a sick passenger—could still put them at risk, even if
these actions do not strictly meet the definition of exposure. (See fig. 4.)
38As of April 2022, for COVID-19, CDC defines exposure as being within 6 feet of
someone who has COVID-19 for a cumulative total of 15 minutes or more over a 24-hour
period.
Page 17 GAO-22-104579 Air Travel and Communicable Diseases
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Figure 4: CDC Guidelines for Potential Exposure to Communicable Diseases in
Flight
Stakeholders Identified a Range of Challenges to
Conducting Needed Research
Stakeholders, including researchers, consumer advocates, and union
representatives, described the following challenges to conducting
research on communicable diseases in air travel:
· Lack of access to aircraft, airports, and relevant data.
Stakeholders said this lack of access is an obstacle to conducting
needed real-world research. One researcher said that ACER, a former
FAA-sponsored Center of Excellence, paired researchers with
industry, and that once that center ended, it became difficult for
researchers to access aircraft.39 Other researchers said that difficulty
accessing aircraft and airports posed a challenge to performing
research on airborne diseases in those environments. The
39We will discuss this center of excellence below. For more information about such
centers, see FAA, “FAA Air Transportation Centers of Excellence,” accessed January 21,
2022, https://www.faa.gov/about/office_org/headquarters_offices/ang/grants/coe.
Page 18 GAO-22-104579 Air Travel and Communicable Diseases
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researchers also stated that it can be difficult to carry out
interdisciplinary research given the complexity of jurisdictions in air
travel. For example, a travel medicine researcher explained that as
passengers move through airports and travel aboard aircraft, they are
under the jurisdiction of local, state, and federal authorities, among
others. Obtaining permission from the appropriate authorities can
present an obstacle to even something as simple as asking
passengers to fill out a questionnaire or collecting a nasal swab.
Finally, researchers across several areas—including government
researchers—told us they could not easily obtain data needed to
improve their models, such as detailed information on cabin
characteristics from aircraft manufacturers or airline-boarding
practices from airlines.
· Lack of sustained support from the federal government and
industry. Researchers told us it has been difficult to obtain federal
support to study communicable diseases in air travel, particularly as
interest in such research has historically waxed and waned with
disease outbreaks. Researchers in several areas also explained that
this interdisciplinary topic may fall in the gaps between different
funding agencies. One researcher told us that if a university-based
scientist went to the National Institutes of Health (NIH) for funding to
study disease transmission in air travel, for example, NIH might
redirect the scientist to CDC, which might, in turn, redirect the scientist
to FAA, which might ultimately say this work is outside its purview.
Another researcher told us that because each agency has its own
niche, it is difficult to find support for needed interdisciplinary work.
Continuity of industry funding for work on communicable diseases can
also be limited. For example, the research assessing passenger
movement and disease transmission on aircraft was conducted with
industry funding and support.40 According to the researchers who
conducted this work, when corporate funding ended, the authors were
not able to pursue follow-on research. One researcher told us that
industry sponsors have a built-in bias to find good news. Similarly,
another researcher said that airlines and airplane manufacturers may
be reluctant to fund or pursue research that could have an adverse
effect on their business, such as research that might suggest changes
to overhead bin access or food and drink service.
40Vicki Stover Hertzberg, et al., “Behaviors, Movements, and Transmission of Droplet-
Mediated Respiratory Diseases during Transcontinental Airline Flights,” Proceedings of
the National Academy of Sciences 115, no. 14 (Apr. 3, 2018): 3623-3727.
Page 19 GAO-22-104579 Air Travel and Communicable Diseases
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· Lack of federal leadership. Given the multiple partners potentially
involved in this interdisciplinary work—including various federal
agencies, as well as academic, nonprofit, and industry
representatives—stakeholders told us that federal leadership is
needed to identify and address gaps in research, corroborate
research findings, and help assure objectivity of research. In
particular, some stakeholders had concerns about the credibility of
industry-funded research. Stakeholders said stronger federal
leadership could bolster public trust in the validity of research findings.
Federal leadership could also facilitate more timely recommendations
to protect the traveling public. With regard to the COVID-19 pandemic
specifically, stakeholders—including researchers with a focus on
ventilation—described inaction or delays in promulgating federal
policies that could better protect passengers, such as requiring that
airlines run aircraft ventilation systems on the ground or that
passengers wear masks.41
Absence of Federal Leadership Has Hindered
the Advancement of Research on
Communicable Diseases in Air Travel
Federal Agencies Have Focused on Research Areas
Relevant to their Missions
While each of the agencies in our review has conducted some research
relevant to communicable diseases in air travel, none of them has
undertaken efforts to advance such research more broadly, according to
agency officials we interviewed. Rather, these agencies have focused on
the specific research areas most relevant to their priorities and mission,
as described above. However, officials with both FAA’s CAMI and CDC’s
Division of Global Migration and Quarantine told us that a more
coordinated federal approach and support for relevant research could
generate valuable information and inform policy development and
guidance. Such research could include studying how people behave
during air travel or the ventilation necessary to protect passengers in
realistic environments, among other areas of research identified by
stakeholders and discussed above.
41ACRP (2013) recommended that aircraft reduce ventilation downtime when parked at
the gate in 2013.
Page 20 GAO-22-104579 Air Travel and Communicable Diseases
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We found that each of the agencies in our review has key expertise and
assets that could be leveraged to identify and advance additional
research that the various stakeholders we interviewed said was needed.
(See table 2.)
Table 2: Examples of Federal Assets and Expertise for Advancing Research on Communicable Diseases in Air Travel
Centers for Disease Control · CDC has broad public health expertise, as well as expertise in epidemiology, which is the study
and Prevention (CDC) of the incidence, distribution, and control of diseases in a population.
· Within the agency, the Division of Global Migration and Quarantine (DGMQ) has access to
findings from ongoing surveillance and contact tracing efforts, and the National Institute for
Occupational Safety and Health (NIOSH) has access to workplace exposure assessments.
· In response to the COVID-19 pandemic, NIOSH developed a research agenda to address
occupational health research gaps, including those affecting airline and airport personnel.
Department of Homeland · DHS’s Science and Technology Directorate has the ability to conduct relevant basic and applied
Security (DHS) research, and the Transportation Security Administration (TSA) has extensive knowledge of the
security process at airports.
· DHS has also developed “master question lists” for several communicable diseases since the
Ebola outbreak in 2014, with key questions that could be addressed through additional
research.a
Federal Aviation Administration · FAA has aeromedical expertise, facilities, and equipment through the Office of Aerospace
(FAA) Medicine and the Civil Aerospace Medical Institute (CAMI).
· In response to the COVID-19 pandemic, FAA has plans to work with public health authorities to
validate ongoing modeling work on disease transmission in the aircraft cabin based on existing
disease transmission models.
· FAA also has established relationships with domestic and international entities involved in the
response to communicable disease threats as they relate to aviation, as well as with
manufacturers.
· The Department of Transportation (DOT) and FAA also have strong ties to key aviation
stakeholders, such as international civil aviation organizations, as well as oversight
responsibilities for airlines, airports, and other members of the aviation industry.
Source: GAO analysis of information from selected federal agencies. │ GAO-22-104579
a
DHS and the Science and Technology Directorate first developed a “master question list” in
response to the 2014–2015 Ebola outbreak to collect high-level research questions derived from
open, reliable, vetted sources. This list allowed the agency to focus on those questions for which the
agency’s response was best qualified. Subsequently, master question lists have been developed for
other topics, including synthetic opioids, African Swine Fever virus, and now COVID-19. For the
dedicated COVID-19 master question list, see DHS “Master Question List for COVID-19 (caused by
SARS-CoV-2),” accessed May 19, 2022,
https://www.dhs.gov/publication/st-master-question-list-covid-19.
Agency officials in our review described challenges to conducting
interdisciplinary research—even among federal agencies. For example, a
CAMI official told us that it is difficult to know what other agencies’
research activities and competencies are, given their overlapping mission
areas and various ways of doing business. Similarly, a NIOSH official told
us that research on communicable diseases in air travel often involves
different areas of expertise and various sectors, making it difficult to
conduct in the absence of leadership to bring entities together. For
Page 21 GAO-22-104579 Air Travel and Communicable Diseases
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example, such research might involve both epidemiological and
engineering expertise as well as public-health and aviation-related data.
In particular, FAA officials stressed the importance of engaging expertise
from various agencies to address challenges posed specifically by the
COVID-19 pandemic. Similarly, officials with DHS’s Science and
Technology Directorate pointed out that the agency has different kinds of
expertise relevant to aircraft cabin exposure research than does FAA.42
We have found in prior work that federal research can benefit from
effective interagency collaboration, such as when the National
Aeronautics and Space Administration (NASA) collaborated with FAA for
technology transfers between these agencies, resulting in the use of
NASA-developed software by FAA’s air traffic controllers.43 Such
coordination can be implemented in a variety of ways, including
developing national strategies and designating leadership.44 In particular,
national strategies can provide a framework for addressing issues that cut
across federal agencies and sectors, while designation of leadership—
such as designating one agency or department to be accountable for a
strategy—can be useful if an effort requires the contribution of several
different agencies exercising different statutory authorities.
We have also found that these approaches can be enhanced and
sustained when they incorporate leading practices for interagency
collaboration, such as clearly identifying roles and responsibilities,
determining resources needed, and documenting any relevant
agreements. A federal strategy that has clear leadership and that
incorporates these leading practices could enable participating agencies
to advance needed research on communicable diseases in air travel in a
coordinated manner and over the long term.
42The Chief Scientist with DHS’s Science and Technology Directorate pointed to differing
areas of research expertise regarding aircraft cabin exposures to illustrate the potential
impact of interagency collaboration. According to this official, while FAA has done
significant work through ACER in the transmission of disease on aircraft and longer-term
exposures on air-cabin quality, DHS’s Science and Technology Directorate and TSA have
done significant work on transmission of bioagents and exposure to toxic chemicals.
43For more information, see GAO-17-372.
44We have previously examined interagency collaborative mechanisms and identified
certain key issues for federal agencies to consider when using these mechanisms to
achieve results. For more information about the key features of interagency collaboration,
see appendix I and GAO-12-1022.
Page 22 GAO-22-104579 Air Travel and Communicable Diseases
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FAA’s Tentative Plan to Continue Research Is Narrow, but
It Has Broad Authority to Do More
While FAA acknowledges that it has broad statutory authority to conduct
and sponsor research related to aviation safety, the extent to which the
agency intends to be involved in research on communicable diseases in
air travel over the long term is unclear. FAA’s plan for research on
communicable diseases in air travel is tentative and narrow, and the
agency currently has no plan to provide sustained support for
interdisciplinary research in this field.
In July 2021, FAA’s Office of Aerospace Medicine issued a strategic plan
for research that included a new focus called “communicable disease
preparedness and response.”45 According to the plan, this effort would
include research on cabin health safety (i.e., the agency’s ongoing
modeling work), as well as potential research addressing COVID-19
effects on medical certification for aviators.46 However, FAA officials
indicated that support and funding for these efforts is uncertain, as the
plan’s execution would be subject to appropriations and congressional
direction. Furthermore, FAA has not made clear whether such an initiative
will be integrated into overall agency priorities for research, particularly
whether it will become part of FAA’s National Aviation Research Plan.
Although FAA is now examining its role in communicable disease
research, it has historically maintained that the risk posed by
communicable diseases in air travel is a public health concern that is
separate from the agency’s core responsibilities for flight safety. FAA
acknowledges that it has broad authority to promote safe flight of civil
aircraft in air commerce by prescribing regulations and minimum
45FAA, Aviation Safety, Aerospace Medicine R&D Strategic Plan (Washington, D.C.: July
17, 2021).
46The plan also includes research support for a portion of the agency’s regulatory portfolio
addressing airman medical certification and may also foreshadow future work addressing
aspects of disease surveillance, although no details are provided for the latter within the
plan.
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standards for a wide range of aviation-safety-related matters.47 In
interviews, however, FAA officials emphasized that health safety is
separate from aviation safety and that, in general, issues related to health
safety—such as an individual’s exposure to pathogens and subsequent
sickness—should be considered public health issues and are the purview
of agencies such as the CDC and HHS. While FAA’s authorities do not
specifically address the protection of crewmembers and passengers
against communicable diseases, such a role in the aviation-safety context
is not necessarily precluded.48
According to FAA, the agency has statutory authority to conduct a wide
range of research and development related to aviation safety, as well as
to make grants to other organizations.49 FAA has previously—although
usually in response to statutory mandates—undertaken research to
address health and safety, including research relevant to communicable
diseases in air travel.50 For example, as previously noted, the agency
sponsored research on the air cabin environment under the aegis of the
National Center of Excellence for Airliner Cabin Environment Research
47Under 49 U.S.C. § 44701, the Administrator of the FAA shall promote safe flight of civil
aircraft in air commerce by prescribing, among other things, “other practices, methods,
and procedure the Administrator finds necessary for safety in air commerce and national
security.” 49 U.S.C. § 44701(a)(5). According to FAA, this authority could potentially
underpin actions taken on the basis of research results if such results provided information
reasonably related to the promotion of the safe flight of civil aircraft in air commerce that
indicated the need for FAA regulatory action.
48According to FAA, applicable statutes and case law provide the FAA with authority to
protect crewmember and passenger health with rules if they are reasonably related to
flight safety. In this light, the D.C. Circuit has held that “‘health’ is a component of ‘safety’”
and includes “protecting passengers’ physical health in flight, even from harms that are
not occasioned by the flight.” Flyers’ Rights Education Fund, Inc. v. FAA, 864 F.3d 738,
748 (D.C. Cir. 2017) (citing Bargmann v. Helms, 715 F.2d 638, 641-43 (D.C. Cir. 1983)
(ruling that FAA has the authority to regulate first aid kits for treating conditions that occur
during the flight, whether or not those conditions are caused by flight conditions or
operations). The D.C. Circuit explained in Flyers’ Rights that “…there is no question that
the Administration has the statutory authority to address at least some passenger health
issues. [citation omitted].” Flyers’ Rights, 864 F.3d at 748. According to FAA, however, the
precise extent to which health and safety overlap in the aviation context is not clearly
defined in the case law.
49See various sections of 49 U.S.C. Chapter 445. For example, pursuant to 49 U.S.C. §
44513, the FAA may make grants to institutions of higher education that are members of
FAA regional centers of air transportation excellence for “aviation safety and security” and
“other aviation issues related to developing and maintaining a safe and efficient air
transportation system.” 49 U.S.C. § 44513(b)(1)(A)(iv), (vi).
50For examples of such research, see appendix III.
Page 24 GAO-22-104579 Air Travel and Communicable Diseases
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(ACER), which FAA established in 2004 in response to congressional
actions.51 For the 10 years that it was in operation, ACER brought
together experts on airliner cabin environments from academic, industry,
and government organizations. ACER published reports on topics such
as disease transmission in airliner cabins, the health effects of aircraft
cabin pressure in older and vulnerable passengers, decontamination
technologies for use on narrow-body and wide-body aircraft, and the
health effects of “bleed air” in aircraft cabins.52 However, outside of work
undertaken in response to statutory mandates, and its recently initiated
modeling work in response to COVID-19, FAA has not independently
pursued research on communicable diseases in air travel since at least
2003.
This previous experience, as well as strong ties with key aviation
stakeholders, suggests that FAA would be best positioned for the lead
role in developing and implementing a strategy to advance research on
communicable diseases in air travel, in coordination with other federal
agencies, such as DHS and HHS, and external stakeholders. Such a
strategy would help focus research efforts to better inform the
development of policies and requirements to protect the health of
passengers and crew. Although agency officials have said the precise
contours of potential FAA authority are not well defined, such a role would
be consistent with DOT’s recent agreement to develop a national
51ACER was established in 2004 by FAA in response to a statutory mandate and
language in a Senate appropriations committee report. Pub. L. No. 108-176, § 815, 117
Stat. 2490, 2592 (2003); S. Rep. No. 108-146 at 28 (2003). According to DOT, in 2014,
the ACER/ACERite Center of Excellence completed mandated tasks and FAA-
sponsorship for the center ended. In general, FAA Air Transportation Centers of
Excellence, such as ACER, are to serve as a primary source of subject-matter expertise
for an agreed upon 10 years. After this time, the Center must be self-supporting to
continue, if agency funding is not extended.
52For example, see ACERite, Infectious Disease Transmission in Airliner Cabins, RITE-
ACER-CoE-2012-01 (Washington D.C.: Feb. 22, 2012), among other studies. After ACER
had ended in 2014, FAA was able to reconvene researchers who had previously been
involved in the Center for cabin air-quality research initiatives focusing more specifically
on “bleed air” and potential contaminants. Bleed air is outside air that is drawn through jet
engines into an aircraft cabin. For more information about bleed air, see Gregory A. Day,
Aircraft Cabin Bleed Air Contaminants: A Review, Civil Aerospace Medical Institute, FAA
(Oklahoma City, OK: November 2015). FAA officials told us that they were subsequently
unable to reconvene this expertise, given that the researchers had largely dispersed and
moved on to other work.
Page 25 GAO-22-104579 Air Travel and Communicable Diseases
Letter
aviation-preparedness plan, as discussed above.53 However, absent
congressional direction, FAA is unlikely to independently adopt such a
leadership role.
Conclusions
The COVID-19 pandemic has intensified ongoing concerns about air
travel’s unique role in spreading disease and raised questions about the
safety of passengers and crew. More interdisciplinary research—
especially involving human behavior and real-world situations—is needed
to better understand the risks of disease transmission in air travel. Such
research could provide insights into the effectiveness of various mitigation
measures and inform the development of evidence-based policy and
requirements to protect public health.
While federal agencies have made some efforts to expand knowledge in
this field, a federal strategy is needed to advance, coordinate, and
leverage this critical research. Bringing various agencies’ assets—
including those of FAA, DHS, and HHS—to bear could link researchers
with aviation stakeholders across areas of expertise, provide clearer
access to federal funding for research, and help identify needed research
across different disciplines. With FAA’s broad authorities to protect
aviation safety and its oversight responsibilities for and ties with aviation
stakeholders, FAA is well positioned to take the lead in developing and
implementing such a strategy. However, FAA officials’ past statements
and responses to our recent inquiries indicate that absent direction from
Congress, the agency is unlikely to assume this role on its own initiative.
53We have recommended that DOT develop a national aviation-preparedness plan for
communicable diseases since 2015 in coordination with relevant stakeholders, such as
HHS and DHS. In April 2020, we had included this open recommendation as one of 16
high priority recommendations to DOT. With the onset of the COVID-19 pandemic, given
DOT’s inaction on this recommendation, we had urged Congress in June 2020 to take
legislative action to require DOT to work with other agencies to develop the plan. As of
July 2022, according to agency officials, DOT plans to take the lead, working closely with
DHS and HHS, in developing such a plan for communicable diseases building upon the
Runway to Recovery (FAA, 2020) and guidance materials from the International Civil
Aviation Organization. According to agency officials, DOT intends to complete and
implement the preparedness plan in 2023. For more information, see GAO-16-127; GAO,
Priority Open Recommendations: U.S. Department of Transportation, GAO-20-513PR
(Washington, D.C.: Apr. 23, 2020); and GAO, Covid-19: Opportunities to Improve Federal
Response and Recovery Efforts, GAO-20-625 (Washington, D.C.: June 25, 2020).
Page 26 GAO-22-104579 Air Travel and Communicable Diseases
Letter
Matter for Congressional Consideration
Congress should consider directing FAA to develop and implement a
strategy to identify and advance needed research on communicable
diseases in air travel, in coordination with appropriate federal agencies,
such as DHS and HHS, and external partners. In alignment with leading
practices for interagency collaboration, this strategy should, at a
minimum, clearly identify the roles and responsibilities for participating
agencies, determine the resources needed, and document any relevant
agreements. (Matter for Consideration 1)
Agency Comments
We provided a draft of this report to DOT, HHS, and DHS for review and
comment. Each of these agencies provided us with technical comments.
Officials with DOT and DHS suggested that the matter for congressional
consideration be directed to all three agencies. We agree that interagency
collaboration will be necessary for the development and implementation
of a national strategy to identify and advance needed research. Given
that DOT and FAA have primary responsibility for overseeing the aviation
sector, we believe that FAA is best positioned to work with relevant
stakeholders to lead this effort. We have added DHS and HHS to our
matter, however, to provide examples of appropriate federal agencies that
should be included in any interagency collaboration.
We are sending copies of this report to the appropriate congressional
committees, the Secretary of Transportation, the Secretary of Health and
Human Services, the Secretary of Homeland Security, and other
interested parties. In addition, the report is available at no charge on the
GAO website at http://www.gao.gov.
If you or your staff have any questions about this report, please contact
Heather Krause at (202) 512-2834 or krauseh@gao.gov. Contact points
for our Offices of Congressional Relations and Public Affairs may be
found on the last page of this report. GAO staff who made key
contributions to this report are listed in appendix IV.
Page 27 GAO-22-104579 Air Travel and Communicable Diseases
Letter
Heather Krause
Director, Physical Infrastructure
Page 28 GAO-22-104579 Air Travel and Communicable Diseases
Letter
List of Committees
The Honorable Patrick Leahy
Chairman
The Honorable Richard Shelby
Vice Chairman
Committee on Appropriations
United States Senate
The Honorable Ron Wyden
Chairman
The Honorable Mike Crapo
Ranking Member
Committee on Finance
United States Senate
The Honorable Patty Murray
Chair
The Honorable Richard Burr
Ranking Member
Committee on Health, Education, Labor, and Pensions
United States Senate
The Honorable Gary C. Peters
Chairman
The Honorable Rob Portman
Ranking Member
Committee on Homeland Security and Governmental Affairs
United States Senate
The Honorable Rosa L. DeLauro
Chair
The Honorable Kay Granger
Ranking Member
Committee on Appropriations
House of Representatives
The Honorable Frank Pallone, Jr.
Chairman
The Honorable Cathy McMorris Rodgers
Republican Leader
Committee on Energy and Commerce
House of Representatives
Page 29 GAO-22-104579 Air Travel and Communicable Diseases
Letter
The Honorable Bennie G. Thompson
Chairman
The Honorable John Katko
Ranking Member
Committee on Homeland Security
House of Representatives
The Honorable Carolyn B. Maloney
Chairwoman
The Honorable James Comer
Ranking Member
Committee on Oversight and Reform
House of Representatives
The Honorable Eddie Bernice Johnson
Chairwoman
The Honorable Frank D. Lucas
Ranking Member
Committee on Science, Space, and Technology
House of Representatives
The Honorable Peter A. DeFazio
Chair
The Honorable Sam Graves
Ranking Member
Committee on Transportation and Infrastructure
House of Representatives
The Honorable Richard E. Neal
Chairman
The Honorable Kevin Brady
Republican Leader
Committee on Ways and Means
House of Representatives
The Honorable Rick Larsen
Chair
The Honorable Garret Graves
Ranking Member
Subcommittee on Aviation
Committee on Transportation and Infrastructure
House of Representatives
Page 30 GAO-22-104579 Air Travel and Communicable Diseases
Appendix I: Objectives, Scope, and
Methodology
Appendix I: Objectives, Scope,
and Methodology
We began this review under GAO’s CARES Act authority.1 We
subsequently received requests from the House Committee on
Transportation and Infrastructure and its Aviation Subcommittee, as well
as the House Committee on Science, Space, and Technology. This report
examines: (1) the status of research on communicable diseases in air
travel, including stakeholders’ views on additional needed research and
challenges to conducting it, and (2) the extent to which FAA and other
federal agencies are advancing such research. For the purposes of our
review, air travel is comprised of passengers’ and crews’ movement
through the airport, on and off aircraft, and in flight, but our scope does
not include air travel’s role in facilitating the spread of a disease to
different locations, or between different modes of transportation (e.g.,
airport to bus or transit system). Our focus is on communicable diseases
that are spread through human contact.2
This report builds on our prior work addressing communicable diseases in
air travel and FAA’s research. In 2015, in response to the Ebola epidemic,
we reviewed the preparedness of the U.S. aviation system to respond to
communicable disease threats, and recommended that the Department of
Transportation (DOT) develop a national aviation-preparedness plan for
communicable diseases, a recommendation that DOT intends to
complete and implement in 2023, according to agency officials.3 In 2017,
we reviewed how FAA manages its research portfolio, and made three
1Pub. L. No. 116-136, § 19010(b), 134 Stat. 281, 579-80 (2020). We regularly issue
government-wide reports on the federal response to COVID-19. For the latest report, see
GAO, COVID-19: Current and Future Federal Preparedness Requires Fixes to Improve
Health Data and Address Improper Payments, GAO-22-105397 (Washington, D.C.: Apr.
27, 2022).
2Some infectious diseases are contagious (or communicable), that is, spread from one
person to another. Other infectious diseases can be spread by germs carried in air, water,
food, or soil. They can also be spread by vectors (like biting insects) or by animals. For
purposes of this report, we are focused on those communicable diseases that might be
spread from person to person during travel.
3GAO, Air Travel and Communicable Diseases: Comprehensive Federal Plan Needed for
U.S. Aviation System’s Preparedness, GAO-16-127 (Washington, D.C.: Dec. 16, 2015).
Page 31 GAO-22-104579 Air Travel and Communicable Diseases
Appendix I: Objectives, Scope, and
Methodology
recommendations that FAA has implemented.4 In June 2020, we provided
a status update on these two earlier reports.5
To examine the status of research on communicable diseases in air travel
and challenges to conducting it, we reviewed academic literature,
monitored relevant news and publications, and interviewed researchers
and other stakeholders, as discussed below. To form the basis of our
review of academic literature, we performed a literature search to identify
research conducted in 2020 on communicable disease transmission and
air travel, including COVID-19, using ProQuest, Dialog, and Scopus. Our
search included results from peer-reviewed scholarly publications,
conference papers, government reports, trade association and think tank
publications, among others, and it excluded general news articles,
working papers, and legislative materials. To better understand how the
volume of research published on communicable diseases in air travel has
changed over time, we performed two additional citation-count searches
in Scopus, for academic journal articles and conference papers published
from January 2011 through July 2021. To stay abreast of relevant
research, we continued to monitor open-source literature through March
2022 and contacted researchers and agency officials.
We interviewed a nongeneralizable selection of stakeholders, including
researchers engaged in relevant work, especially with regard to COVID-
19, as well as aviation stakeholders and agency officials, as described
below. We identified these stakeholders through open-source research,
our literature search, and through interviews. We sought to interview
researchers in a variety of areas (see table 3).
Table 3: Researchers Interviewed to Solicit Views on Communicable Diseases in Air Travel
Research area Researcher Selected relevant research areas
Ventilation and filtration Joe Allen, DSc, MPH, CIH Environmental health, indoor air quality
Linsey Marr, PhD Environmental engineering, bioaerosols, viruses in the built
environment
Donald Milton, MD, DrPH Environmental and occupational health, airborne infection
transmission, bioaerosols
4GAO, Aviation Research and Development: FAA Could Improve How It Develops Its
Portfolio and Reports Its Activities, GAO-17-372 (Washington, D.C.: Apr. 24, 2017).
5GAO, Air Travel and Communicable Diseases: Status of Research Efforts and Action Still
Needed to Develop Federal Preparedness Plan, GAO-20-655T (Washington, D.C.: June
23, 2020).
Page 32 GAO-22-104579 Air Travel and Communicable Diseases
Appendix I: Objectives, Scope, and
Methodology
Research area Researcher Selected relevant research areas
David Silcott Biodefense, bioaerosol detection, sensors
Sean Kinahan Detection and characterization of biological aerosols
Human behavior Vicki Hertzberg, PhD Biostatistics, disease transmission and human behavior on
airplanes
Howard “Howie” Weiss, PhD Microbial genetics, disease dynamics, dynamics of
microbiomes, mathematical modeling
Operations R. John Milne, PhD Operations research methods to determine airplane seat
assignments and passenger boarding sequences
Sirish Namilae, PhD Computational modeling of pedestrian dynamics, multiscale
modeling
Epidemiology/disease David Freedman, MD Infectious diseases, travel medicine, global surveillance of
transmission infectious diseases
Richard Martinello, MD Infectious diseases including molecular epidemiology and the
transmission of respiratory viruses, infection prevention
Robert “Chip” Schooley, MD Infectious diseases including diagnosis, pathogenesis and
therapy of viral infections, global health
Henry Wu, MD Infectious disease epidemiology, travel medicine
Syntheses of existing research Leonard “Lenny” Marcus, PhD Emergency preparedness and response, leadership
Edward “Ed” Nardell, MD Airborne transmission of infectious diseases, infection
prevention strategies
John “Jack” Spengler, PhD Environmental health, indoor air quality
Bioethics Lisa M. Lee, PhD Bioethics, public health and ethics at the local, state, and
federal levels
Source: GAO. │ GAO-22-104579
We also spoke with federal agency officials who might have a research
role related to communicable diseases in air travel. They included officials
at FAA’s Office of Aerospace Medicine and its Civil Aerospace Medical
Institute (CAMI), the National Institute for Occupational Safety and Health
(NIOSH) within the Centers for Disease Control and Prevention (CDC),
and the Department of Homeland Security’s (DHS) Science and
Technology Directorate. In addition, we interviewed the chair of the
Research, Engineering, and Development Advisory Committee (REDAC),
which is the advisory body for FAA’s research portfolio, and officials with
the Airport Cooperative Research Program of the Transportation
Research Board. We spoke with selected aviation stakeholders, as well,
to understand how communicable diseases affect air travel, including the
practical effects of research on policy, including representatives from
unions, aviation industry organizations, and one airline (see table 4).
Table 4: Additional Aviation Stakeholders Interviewed
Air Line Pilots Association https://www.alpa.org/
Page 33 GAO-22-104579 Air Travel and Communicable Diseases
Appendix I: Objectives, Scope, and
Methodology
Airlines for America https://www.airlines.org/
Airport Council International–North America https://airportscouncil.org/
Association of Flight Attendants-CWA https://www.afacwa.org/
Consumer Reports https://www.consumerreports.org/
Delta Air Lines https://www.delta.com/
RTCAa https://www.rtca.org/
Source: GAO. │ GAO-22-104579
a
RTCA, a private nonprofit association founded in 1935 as the Radio Technical Commission for
Aeronautics, is now referred to simply as “RTCA.”
To examine the extent to which FAA and other federal agencies are
advancing research on communicable diseases in air travel, we reviewed
relevant statutes, our prior reports, and documentation of federal
agencies’ actions and plans, such as FAA’s latest National Aviation
Research Plan and presentation materials for REDAC meetings. We also
interviewed officials from DOT’s Office of the Assistant Secretary for
Research and Technology, as well as a variety of FAA offices, including
the Office of Aerospace Medicine and CAMI within it, the Williams J.
Hughes Technical Center, the Office of National Security Programs and
Incident Response, and the Office of Airports and the Flight Standards
Service.
In addition to DOT and FAA, we interviewed officials and reviewed
documentation from other selected relevant agencies, including the
Division of Global Migration and Quarantine (DGMQ) and NIOSH at the
CDC, and the Transportation Security Administration (TSA) and the
Science and Technology Directorate at DHS. In addition to these
agencies, we solicited input from the National Institute of Allergy and
Infectious Diseases (NIAID) at the National Institutes of Health (NIH). We
identified these agencies based on our initial entrance with FAA and
internal discussions with GAO stakeholders. We also reviewed mission
statements, research plans, and other relevant documentation, for
DGMQ, NIOSH, NIAID, and TSA, in addition to conducting interviews or
collecting written responses from each of these agencies.
We assessed key considerations for interagency collaboration, including
collaborative mechanisms and associated leading practices identified in
Page 34 GAO-22-104579 Air Travel and Communicable Diseases
Appendix I: Objectives, Scope, and
Methodology
our prior work.6 This work identifies “collaboration” broadly as any joint
activity that is intended to produce more public value than could be
produced when agencies act alone. Table 5 includes key features of
effective interagency collaboration. For the purposes of a collaborative
strategy for research on communicable diseases in air travel, relevant
features include identifying leadership, clarifying roles and
responsibilities, determining resources needed, and documenting relevant
agreements.
Table 5: Key Features of Effective Interagency Collaboration
Outcomes and Have short-term and long-term outcomes been clearly
Accountability defined? Is there a way to track and monitor their progress?
Bridging Organizational What are the missions and organizational cultures of the
Cultures participating agencies? Have agencies agreed on common
terminology and definitions?
Leadership How will leadership be sustained over the long-term? If
leadership is shared, have roles and responsibilities been
clearly identified and agreed upon?
Clarity of Roles and Have participating agencies clarified roles and
Responsibilities responsibilities?
Participants Have all relevant participants been included? Do they have
the ability to commit resources for their agency?
Resources How will the collaborative mechanism be funded and
staffed? Have online collaboration tools been developed?
Written Guidance and If appropriate, have participating agencies documented their
Agreements agreements regarding how they will be collaborating? Have
they developed ways to continually update and monitor
these agreements?
Source: GAO. │ GAO-22-104579
We conducted this performance audit from October 2020 to July 2022 in
accordance with generally accepted government auditing standards.
Those standards require that we plan and perform the audit to obtain
sufficient, appropriate evidence to provide a reasonable basis for our
findings and conclusions based on our audit objectives. We believe that
the evidence obtained provides a reasonable basis for our findings and
conclusions based on our audit objectives.
6See GAO, Managing for Results: Key Considerations for Implementing Interagency
Collaborative Mechanisms, GAO-12-1022 (Washington, D.C.: Sep. 26, 2012). Prior GAO
work applies key features of interagency collaboration from this work to research in
GAO-17-372 and GAO, Antibiotic Resistance: Additional Federal Actions Needed to Better
Determine Magnitude and Reduce Impact, GAO-20-341 (Washington, D.C.: Mar. 30,
2020).
Page 35 GAO-22-104579 Air Travel and Communicable Diseases
Appendix II: Selected Research on
Communicable Diseases in Air Travel
Appendix II: Selected Research
on Communicable Diseases in Air
Travel
We identified research done in a variety of areas as part of our review on
the status of research on communicable diseases in air travel. For
example, we found studies assessing different queuing and boarding
techniques (e.g., from the rear of the plane), which were conducted by
university researchers with expertise in operations or engineering using
computer models. We also identified an initiative to synthesize existing
research on the effects of layered mitigations in reducing disease
transmission in air travel that had been conducted by university
researchers with the support of industry. Table 6 includes selected
citations for areas of research that we identified as being relevant for
COVID-19.
Table 6: Selected References for Research Areas Related to Communicable Diseases in Air Travel
Selected research areas Selected citations
Ventilation and filtration Bull, Karen. “Cabin Air Filtration: Helping to Protect Occupants From Infectious Diseases.” Travel
Medicine and Infectious Disease 6 (2008): 142–144. https://doi.org/10.1016/j.tmaid.2007.08.004.
Dai, Hui, Zhao, Bin. “Association of the Infection Probability of COVID-19 with Ventilation Rates in
Confined Spaces. Building Simulation 13, (2020): 1321–1327.
https://doi.org/10.1007/s12273-020-0703-5.
TRANSCOM/AMC Commercial Aircraft Cabin Aerosol Dispersion Tests, submitted to U.S.
Transportation Command (TRANSCOM) and Air Mobility Command (AMC) (Oct. 28, 2020).
Human behavior Hertzberg, Vicki Stover, Howard Weiss, Lisa Elon, Wenpei Si, Sharon L. Norris, and The FlyHealthy
Research Team. “Behaviors, Movements, and Transmission of Droplet-Mediated Respiratory
Diseases during Transcontinental Airline Flights.” Proceedings of the National Academy of Sciences
115, no. 14 (National Academy of Sciences, 2018): 3623-3627.
https://doi.org/10.1073/pnas.1711611115.
Page 36 GAO-22-104579 Air Travel and Communicable Diseases
Appendix II: Selected Research on
Communicable Diseases in Air Travel
Selected research areas Selected citations
Operations Derjany, P., S. Namilae, D. Liu, and A. Srinivasan. “Multiscale Model for the Optimal Design of
Pedestrian Queues to Mitigate Infectious Disease Spread.” Plos One 15, no. 7 (2020).
https://doi.org/10.1371/journal.pone.0235891.
Dietrich, Watts L., James S. Bennett, Byron W. Jones, and Mohammad H. Hosni. “Laboratory
Modeling of SARS-CoV-2 Exposure Reduction through Physically Distanced Seating in Aircraft Cabins
using Bacteriophage Aerosol - November 2020.” MMWR - Morbidity and Mortality Weekly Report 70,
no. 16 (April 23, 2021): 595-599. https://doi.org/10.15585/mmwr.mm7016e1.
Milne, R. John, Camelia Delcea, and Liviu-Adrian Cotfas. “Airplane Boarding Methods that Reduce
Risk from COVID-19.” Safety Science 134, (2021). https://doi.org/10.1016/j.ssci.2020.105061.
Salari, Mostafa, R. J. Milne, Camelia Delcea, and Liviu-Adrian Cotfas. “Social Distancing in Airplane
Seat Assignments for Passenger Groups,” Transportmetrica B: Transport Dynamics, 10:1 (2022):
1070-1098. https://doi.org/10.1080/21680566.2021.2007816.
Tande, Aaron J. et al. “SARS-CoV-2 Testing Prior to International Airline Travel, December 2020-May
2021.” Mayo Clinic Proceedings 96, no. 11 (November 2021): 2856-2860.
https://doi.org/10.1016/j.mayocp.2021.08.019.
Epidemiology/disease Freedman, David O. and Annelies Wilder-Smith. “In-Flight Transmission of SARS-CoV-2: A Review of
transmission the Attack Rates and Available Data on the Efficacy of Face Masks.” Journal of Travel Medicine 27,
no. 8 (December 2020). https://doi.org/10.1093/jtm/taaa178.
Hu, Maogui, Jinfeng Wang, Hui Lin, Corrine W. Ruktanonchai, Chengdong Xu, Bin Meng, Xin Zhang,
et al. “Risk of SARS-CoV-2 Transmission among Air Passengers in China.” Clinical Infectious
Diseases (2021). https://doi.org/10.1093/cid/ciab836.
Yang, Wan, Subbiah Elankumaran, and Linsey C. Marr. “Concentrations and Size Distributions of
Airborne Influenza A Viruses Measured Indoors at a Health Centre, a Day-Care Centre and on
Aeroplanes.” Journal of the Royal Society, Interface 8, no. 61 (2011): 1176-1184.
https://doi.org/10.1098/rsif.2010.0686.
Syntheses of existing Chu, Derek K., Elie A. Akl, Stephanie Duda, Kara Solo, Sally Yaacoub, and Holger J. Schünemann.
research “Physical Distancing, Face Masks, and Eye Protection to Prevent Person-to-Person Transmission of
SARS-CoV-2 and COVID-19: A Systematic Review and Meta-analysis.” Lancet 395, no. 10242 (June
27, 2020): 1973-1987. https://doi.org/10.1016/S0140-6736(20)31142-9.
Marcus, L. Assessment of Risks of SARS-CoV-2 Transmission during Air Travel and Non-
Pharmaceutical Interventions to Reduce Risk, Phase One Report: Gate-to-Gate Travel Onboard
Aircraft, Harvard T.H. Chan School of Public Health, 2020.
———. Assessment of Risks of SARS-CoV-2 Transmission during Air Travel and Non-Pharmaceutical
Interventions to Reduce Risk, Phase Two Report: Curb-to-Curb Travel through Airports: Aviation
Public Health Initiative, Aviation Public Health Initiative, Harvard T.H. Chan School of Public Health,
2021.
Transportation, Research Board and National Academies of Sciences, Engineering, and Medicine.
Infectious Disease Mitigation in Airports and on Aircraft, edited by Environmental Health &
Engineering, Inc. Washington, DC: The National Academies Press, 2013.
https://doi.org/10.17226/22512.
Page 37 GAO-22-104579 Air Travel and Communicable Diseases
Appendix II: Selected Research on
Communicable Diseases in Air Travel
Selected research areas Selected citations
Reports by Airliner Cabin Chen, Q., B. W. Jones, S. M. Loo, W. W. Nazaroff, R. A. Overfelt, J. D. Spengler, C. P. Weisel, and C.
Environment Research J. Weschler. Report to the FAA Airliner Cabin Environment: National Air Transportation Center of
(ACER) Program Center of Excellence for Research in the Intermodal Transport Environment (RITE), 2010.
Excellence Chen, Q., J. J. McDevitt, J. K. Gupta, B. W. Jones, S. Mazumdar, S. B. Poussou, and J. D. Spengler.
Infectious Disease Transmission in Airliner Cabins: National Air Transportation Center of Excellence
for Research in the Intermodal Transport Environment (RITE), 2012.
Gale, William F., Hyacinth S. Gale, Jean Watson, Airliner Cabin Environment Research (ACER)
Program. Field Evaluation of Whole Airliner Decontamination Technologies for Narrow-Body Aircraft,
2008.
Gale, William F., Hyacinth S. Gale, Jean Watson, Airliner Cabin Environment Research (ACER)
Program. Field Evaluation of Whole Airliner Decontamination Technologies - Wide-Body Aircraft with
Dual-use Application for Railcars, 2008.
McNeely, Eileen, John Spengler, and Jean Watson. Health Effects of Aircraft Cabin Pressure in Older
and Vulnerable Passengers: National Air Transportation Center of Excellence for Research in the
Intermodal Transport Environment (RITE), 2011.
Source: GAO analysis of literature related to research on communicable diseases in air travel. │ GAO-22-104579
Page 38 GAO-22-104579 Air Travel and Communicable Diseases
Appendix III: FAA Health and Safety Research
Mandated by Statute
Appendix III: FAA Health and
Safety Research Mandated by
Statute
The Federal Aviation Administration (FAA) has undertaken research
addressing health and safety in the past in response to statutory
mandates. For example, several laws have been enacted requiring FAA
to study cabin air quality and associated health effects. A selection of
these laws and research work since 1994 is shown in figure 5.1
Figure 5: Federal Aviation Administration’s (FAA) Responses to Statutory Mandates for Research on Cabin Air Quality and
Health Effects (1994 through 2020)
1FAA cabin air-quality research initiatives after 2014 focus more specifically on “bleed air”
and potential contaminants. Bleed air is outside air that is drawn through jet engines into
an aircraft cabin. For more information about bleed air, see FAA, Civil Aerospace Medical
Institute, Aircraft Cabin Bleed Air Contaminants: A Review (Oklahoma City, OK:
November 2015).
Page 39 GAO-22-104579 Air Travel and Communicable Diseases
Appendix IV: GAO Contact and Staff
Acknowledgments
Appendix IV: GAO Contact and
Staff Acknowledgments
GAO Contact
Heather Krause, (202) 512-2834 or krauseh@gao.gov
Staff Acknowledgments
In addition to the contact named above, Jean Cook (Assistant Director);
Molly Laster (Analyst in Charge); Paul Aussendorf; Susan Bernstein;
Karen Doran; Camilo Flores-Monckeberg; Geoffrey Hamilton; Hayden
Huang; Dan Luo; Brittaini Maul; Jonathan Munetz; Mona Nichols Blake;
Josh Ormond; Kelly Rubin; Pam Snedden; and Laurel Voloder made key
contributions to this report.
(104579)
Page 40 GAO-22-104579 Air Travel and Communicable Diseases
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