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May 3, 2021
Origins of SARS-CoV-2
In late 2019, a new coronavirus, SARS-CoV-2, was
transmitted it to humans. No intermediate hosts have been
identified in Wuhan, China. The virus, which causes
Coronavirus Disease 2019 (COVID-19), has contributed to
(2) Direct zoonotic spillover, a “possible-to-likely
significant morbidity (illness) and mortality (death), as well
pathway through which SARS-CoV-2 could have been
as severe public health and economic effects, among other
transmitted from an animal reservoir host to a human. Bats
impacts. Several Members of Congress have made public
are seen as a likely reservoir host, as several studies have
statements and introduced legislation calling for an
identified high genetic similarity between SARS-CoV-2
investigation into the origin of SARS-CoV-2. Determining
and coronaviruses found in certain bat species found in
the origin and pathway by which a zoonotic disease (i.e.,
China and elsewhere in South Asia.
one that originated in animals) emerges and is transmitted
to humans can help scientists prevent further outbreaks,
(3) Introduction through cold/food-chain products, a
inform the public health response, and aid in the
possible” hypothesis positing that people contracted
development of therapeutics and vaccines. Further, such
SARS-CoV-2 through contact with contaminated food,
knowledge may guide the development of policies and
potentially including frozen, imported foodstuffs. SARS-
practices that reduce the potential for the emergence of
CoV-2 has been identified on frozen food, its packaging,
other zoonotic diseases. Scientists note that determining the
and cold-chain products (items stored at controlled
origin of zoonotic diseases could take years, and in some
temperatures to preserve and extend shelf life).
cases, an origin may never be conclusively identified.
(4) Introduction through a laboratory incident, an
In May 2020, the 73rd World Health Assembly (WHA)—
extremely unlikely” hypothesis considering whether
the governing body of the World Health Organization
laboratory staff accidentally contracted and later spread
(WHO)—passed a resolution (WHA 73.1) requesting the
SARS-CoV-2 while researching coronaviruses in bats. The
WHO Director-General to identify the source of SARS-
WHO report did not consider a hypothesis that the virus
CoV-2 and the route of transmission to humans, among
was released intentionally, stating that it had been ruled out
other things. WHO sent a team to China in July 2020 to
by other scientists.
develop a work plan and begin collecting and analyzing
data, including
Ultimately, the investigators did not identify the source of
SARS-CoV-2 and recommended further studies. The team
 studies of all-cause mortality and deaths from
also called for regular administrative and internal reviews
respiratory diseases, including pneumonia, in and
of high-level biosafety laboratories worldwide to address
around Wuhan in late 2019;
what they characterized as the need for more data.
 testing of stored animal samples for SARS-CoV-2;
U.S. Government Response to the Report

On March 30, 2021, the United States and 13 other
national disease surveillance data; and
countries issued a joint statement expressing concerns “that
 reports of retail pharmacy purchases of medicines to
the international expert study on the source of the SARS-
reduce fevers and treat cold and flu symptoms.
CoV-2 virus was significantly delayed and lacked access to
complete, original data and samples.” The statement also
From January 14 through February 10, 2021, a team of 34
called for immediate movement to a second phase of
experts—17 from China and 17 from other countries and
investigation and that future missions be free to produce
organizations—traveled to Wuhan to collect and analyze
independent and objective recommendations and findings.
existing and additional data. On March 30, 2021, WHO
The signatories expressed continued support for WHO and
released its report on the mission, which summarized
urged further studies to determine SARS-CoV-2 origins.
findings from site visits and discussions with Chinese local
and national experts. The report presented four hypotheses
U.S. Efforts to Control Zoonotic Diseases
on the origin of SARS-CoV-2 and assessed their likelihood
For decades, U.S. federal agencies have worked to
of being the cause.
strengthen international biosecurity and advance global
pandemic preparedness. These efforts are aimed at averting
Origin Hypotheses: Independent Team Findings
the likelihood that scenarios listed in the hypotheses might
Hypotheses on SARS-CoV-2 origins follow and are
occur. This section summarizes selected efforts related to
illustrated in Figure 1. The team’s findings are italicized.
the four hypotheses.
(1) Introduction through an intermediate host, a “likely-
” hypothesis that an intermediate host species,
infected by an animal reservoir host (the animal where the
virus lives, grows, and multiplies), carried the virus and

Origins of SARS-CoV-2
Figure 1. Possible SARS-CoV-2 Origins
collections. The State Department’s Biosecurity
Engagement Program works with scientists in partner
countries to improve biosecurity practices.
Issues for Congress
Scenarios 1 and 2.
The transmission of zoonotic diseases is
facilitated by close human-animal contact, which may occur
via land clearing, live animal markets, hunting and
consuming wild animals, and the wildlife trade. Several
bills in the 117th Congress aim to improve global pandemic
preparedness (e.g., H.R. 391, which also authorizes the
aforementioned GHSA coordinating mechanism to ensure
its continuation under future Administrations). Other bills
(e.g., S. 37 and H.R. 151) would directly address zoonotic
diseases by supporting a reduction in illegal and legal
wildlife trade, seeking to curb deforestation and destruction
of ecosystems, and enhancing international collaboration.
An April 2021 statement from WHO and other U.N.
agencies to reduce public health risks associated with
wildlife markets and the sale of live wild animals may
further increase congressional interest in these issues.
Scenario 3. The international community, including
USDA, United Nations Food and Agriculture Organization,

and the World Trade Organization, via its Market
Source: Graphics created by CRS from WHO, WHO-Convened
Facilitation Agreement, could facilitate global
Global Study of Origins of SARS-CoV-2, March 30, 2021.
implementation of food safety regulations that include
Scenarios 1 and 2. Several U.S. agencies are involved in
analysis and control of biological, chemical, and physical
global control of zoonotic infectious diseases, primarily the
hazards from raw materials to finished products. Proponents
U.S. Agency for International Development (USAID) and
of global regulations say that such policies could strengthen
CDC. The agencies address connections among people,
food safety standards. Proponents assert that greater global
animals, and the environment, described as a One Health
coordination on food regulations could reduce the risk of
approach. They also collaborate with the U.S. Department
disease emergence and transmission in countries where
of Agriculture (USDA) on livestock and poultry health and
current regulations are relatively lax. It is unclear whether
with the Department of the Interior, which monitors
FSIS is inspecting food for SARS-CoV-2, since FDA
wildlife hosts and zoonotic pathogens, and emerging
considers SARS-CoV-2 transmission through contaminated
zoonotic diseases. On January 20, 2021, President Joseph
food or surfaces generally unlikely. Congress might
R. Biden, Jr. issued an executive order establishing the
consider the possibility that the virus could be transmitted
National Security Council Directorate on Global Health
through the cold food chain and expanding the capacity of
Security and Biodefense, which oversees the Global Health
FSIS to conduct inspections for zoonotic diseases from
Security Agenda (GHSA) Interagency Review Council.
foods of certified foreign food exporters.
One task of this council is to monitor current and emerging
Scenario 4. Several Members of Congress have expressed
biological threats, including emerging zoonotic pathogens.
concern about what they characterize as disjointed
Scenario 3. Many foreign countries do not have adequate
biosecurity efforts across the U.S. government. In response
food cold chains. Instead, perishable products from wet
to this concern, P.L. 116-283, the National Defense
markets—where a variety of different meats, including wild
Authorization Act for FY2021, directed the Office of
game can, be sold in close proximity—may be transferred
Management and Budget (OMB), in conjunction with the
without refrigeration. Several USDA agencies, under the
Department of Health and Human Services (HHS), to
coordination of the Foreign Agricultural Service (FAS)—
develop a government-wide budget for biodefense. The act
which leads U.S. global negotiations on international food
also directs the Secretaries of HHS, Defense, Agriculture,
standards—are engaged in improving cold chains
Homeland Security, and any other agencies, in consultation
worldwide, particularly for improving food safety and
with the Assistant to the President for National Security
minimizing risks of zoonosis. In addition, USDA’s Food
Affairs and the OMB Director, to update the 2019 National
Safety and Inspection Service (FSIS) and Animal Plant
Biodefense Implementation Plan. Congress may consider
Health Inspection Service (APHIS) certify foreign products
overseeing the effectiveness of these efforts.
and establishments that meet U.S. standards as being
eligible to export their products to the United States.
Tiaji Salaam-Blyther, Specialist in Global Health
Pervaze A. Sheikh, Specialist in Natural Resources Policy
Scenario 4. Several U.S. federal agencies are involved in
Hassan Z. Sheikh, Analyst in Public Health Emergency
improving partner countries’ biosafety and biosecurity
(BS&S) and biosurveillance capabilities to reduce the threat
Sara M. Tharakan, Analyst in Global Health and
of intentional, accidental, or natural spread of infectious
disease. Department of Defense assistance, for example,
International Development
aims to improve BS&S at laboratories housing pathogen

Origins of SARS-CoV-2

Mary Beth D. Nikitin, Specialist in Nonproliferation
Randy Schnepf, Specialist in Agricultural Policy

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