SAGO’s independent assessment says the weight of available scientific evidence supports a zoonotic origin for SARS-CoV-2, but it also states that the origins remain inconclusive because essential information was not provided. The report says a laboratory-related incident cannot be ruled out, and it also cannot be proven without more information.

The WHO Scientific Advisory Group for the Origins of Novel Pathogens concluded that the most supported hypothesis is zoonotic spillover, either directly from bats or through an intermediate host. It also said that all hypotheses must remain on the table because key data needed to assess a laboratory leak were not shared.

The IC assesses that SARS-CoV-2, the virus that causes COVID-19, probably emerged and infected humans through an initial small-scale exposure that occurred no later than November 2019 with the earliest known COVID-19 cluster appearing in December 2019. One IC element assesses with moderate confidence that the first human infection with SARS-CoV-2 most likely was the result of a laboratory-associated incident, probably involving experimentation, animal handling, or sampling by the Wuhan Institute of Virology. Other agencies assess, with low confidence, that a natural exposure to an infected animal or infected animal products is the most likely scenario, and the IC assesses that SARS-CoV-2 probably was not genetically engineered.

Using genomic analyses and epidemiologic evidence, the authors concluded that a natural origin of SARS-CoV-2 was more likely than a laboratory origin. The paper states that no scientific data exist to support a lab leak of SARS-CoV-2 and that available evidence is consistent with wildlife emergence.

The Lancet article summarizing the SAGO report says the assessment reflects four hypotheses, including two laboratory-accident scenarios, but notes that the evidence available to SAGO most strongly supported zoonotic spillover. It also says WHO and SAGO had requested further information from China, Germany, and the United States, and that the information had not been provided at the time of writing.

The WHO report released today found no compelling evidence that scientists created SARS-CoV-2. It said there is still not enough hard evidence to determine whether the virus arose from natural spillover or a laboratory leak, and it quoted the report as saying that no evidence had been presented beyond speculation that supports a laboratory-related incident causing spread into humans.

This preprint reports that a large set of public scientific statements was coded into two hypotheses, lab leak and natural origin, to quantify consensus amid political narratives. The abstract indicates the work is about measuring how scientific consensus is distributed between the two origin hypotheses, not establishing a direct origin finding itself.

The SAGO report says there had been no new data made available to evaluate a laboratory pathway for SARS-CoV-2 entering humans, and it recommended further investigations into that possibility and all other possible pathways. This is not a finding that a lab escape occurred; it is a statement that the lab hypothesis could not then be fully assessed.

The lab leak hypothesis postulates that researchers constructed or simply cultured SARS-CoV-2 during research on bat-origin coronaviruses and that an accident at the Wuhan Institute of Virology or another facility released the virus into the human population. Early isolates of SARS-CoV-2 show the furin cleavage site to be intact, arguing against introduction into humans after laboratory cell culture, in which deletion of this site is expected and would constitute a signature of laboratory handling. While various papers have suggested that SARS-CoV-2 carries hallmarks of recombinant DNA technologies, this theory has been thoroughly refuted, including by the U.S. intelligence community, and the collective evidence favors a zoonotic origin over a lab leak. Early cases in Wuhan involved two lineages, distinguishable by the viral genome sequence, suggesting multiple spillover events into humans; both lineages were found in sequences from the Huanan market and this situation is more likely to have resulted from zoonosis than a lab accident.

The U.S. Intelligence Community (IC) has concluded it doesn’t have enough information to resolve whether the COVID-19 pandemic began because of a natural jump of SARS-CoV-2 from animals to humans or a laboratory accident. The first, and most important, takeaway is that the IC is “divided on the most likely origin” of the pandemic coronavirus and that both hypotheses are “plausible.” There was “low confidence” by some groups involved that SARS-CoV-2 had a natural origin, but only one IC element had moderate confidence the virus came from a lab. The agencies also concluded that “the virus was not developed as a biological weapon.”

The director of the US Office of the Director of National Intelligence (ODNI) on June 23 issued a declassified report on what US intelligence agencies know about potential links between the Wuhan Institute of Virology (WIV) and the origin of the SARS-CoV-2 virus. In early March, both houses of Congress passed a bill to declassify what US agencies found, following reports that two—the Federal Bureau of Investigation (FBI) and the Department of Energy (DOE)—found with low confidence that a lab leak was the most likely source. Others, also with low confidence, said a jump from animals to humans was the most likely source. Four agencies still lean toward the natural origin source, while the FBI and DOE still lean toward a lab leak, according to the Associated Press. Two others, including the Central Intelligence Agency, have not made assessments.

The report says the hypotheses fall into two broad groups: zoonotic spillover and laboratory accident. It concludes that the weight of available evidence suggests zoonotic spillover, while emphasizing that the lack of raw data prevents certainty about the exact route into the human population.

Available evidence indicates that SARS‑CoV‑2 was originally harbored by bats and transmitted to humans through infected wild animals serving as intermediate hosts at the Huanan Seafood Market in Wuhan, Hubei, China, in December 2019. There is no evidence supporting laboratory involvement, no indication that the virus existed in any lab prior to the pandemic, and no record of suspicious biosecurity incidents. A declassified June 2023 Office of the Director of National Intelligence report found no evidence of SARS‑CoV‑2 in labs or biosafety incidents but could not rule out a leak; most U.S. intelligence agencies (with low confidence) favored zoonotic origin, while one element assessed a lab-associated incident as more likely.

The report, which was released on August 27, noted that the Intelligence Community did not reach a unanimous conclusion on the origin of the virus, with four agencies determining that the index case was likely a result of natural exposure, with another agency considering it as the result of a laboratory incident, although the community overall agreed that it was not linked to biological warfare. It states that SARS-CoV-2, the virus responsible for COVID-19, "probably emerged and infected humans through an initial small-scale exposure that occurred no later than November 2019", with the first outbreak in Wuhan dating back to December 2019. Four agencies, as well as the National Intelligence Council, assessed "with low confidence" that the initial SARS-CoV-2 infection was most likely caused by natural exposure to an infected animal or a "close progenitor virus"… Another agency assessed "with moderate confidence" that the first human infection was most likely the result of a laboratory incident… In June 2023, the Office of the Director of National Intelligence released a new declassified document, which said that the Intelligence Community had still not reached a consensus on the origin of the virus and was unable to rule out the lab leak theory.

This article says the majority of the scientific community still shares the assumption that SARS-CoV-2 likely jumped to humans through natural means, most likely from a bat via an intermediate animal host. It also states that neither the zoonotic-origin nor lab-origin hypothesis is currently fully substantiated.

Validating the lab leak hypothesis requires intelligence evidence that the WIV possessed or carried out work on a SARS-CoV-2 precursor virus, performed experiments that could have plausibly generated SARS-CoV-2, and breached containment, or evidence that SARS-CoV-2 was present in laboratory samples before it appeared in humans. No such public evidence currently exists. Instead, the hypothesis has been promoted largely through speculation based on coincidences of geography and timing, selective use of partial data, and misrepresentation of virology practices. The continued promotion of the lab leak hypothesis in the absence of supporting evidence has harmed trust in science and global health institutions.

A University of Utah summary of a Cell review reports that there is no evidence that researchers at the Wuhan Institute of Virology worked with SARS-CoV-2 or a closely related virus, and that none of the first documented cases were near the institute. The summary says the authors judged a lab accident to be highly unlikely, while not ruling it out completely.

The CIA said Saturday it has shifted its previous assessments and has concluded that it's likely the Covid‑19 virus was leaked from a Chinese lab before it spread worldwide. However, the agency noted that it holds "low confidence" in this conclusion, meaning the judgment is based on sparse, questionable, or fragmented information. A spokesperson for the CIA stated that the agency assesses with low confidence that a research‑related origin of the COVID‑19 pandemic is more probable than a natural origin, based on the existing body of reports, while emphasizing that both scenarios—research‑related and natural origins—remain possible.

The Department of Energy says it is "likely" that Covid‑19 stemmed from an accidental laboratory leak in China, according to two sources with direct knowledge of the intelligence. The DOE's judgment comes with "low confidence," meaning its credibility is limited and based on incomplete or questionable information. Other U.S. agencies have reached different conclusions or remain undecided, contributing to a divided intelligence community assessment on whether the pandemic originated from a lab leak or natural spillover.

The weekend release of the US Central Intelligence Agency (CIA) report favouring a laboratory leak as the likely origin of COVID-19 – albeit with “low confidence” – has reignited a vitriolic debate. However, the CIA added that it “continues to assess that both research-related and natural origin scenarios of the Covid-19 pandemic remain plausible”. The failure of the Chinese government to allow independent scientists access to Wuhan, COVID-19’s “ground zero”, and various data sets, means that conclusive evidence to support one or other thesis is unlikely.

The so‑called "lab‑leak theory" suggests that a new variant may have accidentally escaped from the Wuhan Institute of Virology (WIV) during serial passage or gain‑of‑function research on SARS‑related viruses. Some circumstantial evidence seems to support this theory, such as reports that some WIV researchers showed COVID‑like symptoms early on, records of high‑risk coronavirus experiments led by Dr. Shi Zhengli’s team, and the fact that the earliest outbreak occurred in Wuhan. However, the viruses used in these experiments were not physically present but rather consisted of synthesized genetic sequences, meaning they were not complete, nor infectious viral particles capable of replication, and the pseudo‑virus experiments conducted to test human cell entry lacked the ability to replicate. Dr. Shi Zhengli has consistently emphasized from the outset that the virus was unrelated to their laboratory work.

Newly released FOIA records show that the Defense Intelligence Agency (DIA) was evaluating a detailed lab-origin scenario tied to a Wuhan lab in March 2020 — weeks into the pandemic and well before the issue became a subject of public debate. On a previously published slide headed “Hypothetical Laboratory Origin of SARS-CoV-2,” the assessment sketches a step-by-step timeline of real and speculative work at the WIV that explains the techniques for how the virus that caused the pandemic could plausibly have been created in a lab with insufficient biosecurity containment. A comment bubble appended to a list of observations about WIV’s capabilities reads: “The molecular biology capabilities of WIV and the genomic assessment are consistent with the hypothesis that SARS-CoV-2 was a lab-engineered virus that was part of a bank of chimeric viruses in Zhengli Shi’s laboratory at WIV that escaped from containment.” The newly released records show that even though the agency quickly outlined and seriously considered a detailed lab-origin hypothesis, the March 2020 authoritative assessment formally concluded that the virus’s origins “remain unknown.”

Germany's foreign intelligence service, the Bundesnachrichtendienst (BND), believed there was an 80–90% chance that coronavirus accidentally leaked from a Chinese lab, German media say. Reports indicate that the BND deemed the lab theory as "likely," despite lacking conclusive evidence, and that the agency discovered signs of multiple safety regulation violations at the laboratory. China's foreign ministry responded by asserting that the origins of the virus "should be determined by scientists" and referred to a China‑WHO joint expert team that had previously concluded that a laboratory leak was "extremely unlikely" after site visits and discussions with researchers in Wuhan.

Evidence released by the intelligence community provides further proof that COVID-19 originated in a Wuhan laboratory. Expert witnesses testified that current American intelligence and intelligence during the height of the pandemic support the lab leak as the only credible explanation for the origination of COVID-19. Former Director Ratcliffe issued a bombshell statement in his opening remarks that current intelligence supports the lab leak as the only credible explanation for the origination of COVID-19: “My informed assessment… has been and continues to be that a lab leak is the only explanation credibly supported by our intelligence, by science and by common sense.” Committee leaders argued that “our intelligence has led to a demonstrable shift whereby a few of the intelligence community’s 18 agencies are now publicly assessing that the COVID-19 virus originated from a lab leak in Wuhan.”

The CIA has “low confidence” in its assessment that the COVID-19 virus more likely came from a lab rather than natural transmission. Analysts explained that “low confidence” means the information supporting the judgment is scant, questionable, or fragmented, and that stronger evidence would be required to move to moderate or high confidence. The video underscores that the CIA still considers both lab-related and natural origin scenarios plausible and that the lack of direct evidence from China limits firm conclusions.

The article reports that SAGO said all hypotheses remain on the table, including zoonotic spillover and a lab leak, because China had not shared the requested genetic sequences, animal-market information, or laboratory biosafety information. As a secondary report, it mirrors the WHO position that the evidence remains incomplete.

By nearly all measures of science, if there was evidence of a natural origin it would have already surfaced. But it hasn't. The article argues that "data shows that all COVID‑19 cases stem from a single introduction into humans" and claims this runs contrary to previous pandemics where there were multiple spillover events. It highlights that Wuhan is home to China’s foremost SARS research lab, which has conducted gain‑of‑function research at inadequate biosafety levels, and asserts that "a lab‑related incident involving gain‑of‑function research is the most likely origin of COVID‑19." These conclusions challenge the prevailing view in many scientific and official assessments, which either favor a zoonotic origin or describe the evidence for a lab leak as speculative.

In July 2022, two articles appeared in the journal Science analyzing all available epidemiological and genetic evidence from the earliest known cases in Wuhan. Based on two different analyses, the authors of both papers concluded that the outbreak began at the Huanan Seafood Wholesale Market and was unconnected to any laboratory. A third study examined RNA samples taken directly from the market in spring 2020 and detected SARS‑CoV‑2 RNA in environmental samples collected from animal stalls and sewage wells at the market, supporting a scenario in which infected animals at the market seeded the outbreak. There is a scientific consensus that SARS‑CoV‑2 is not the result of genetic engineering.

Wikipedia’s summary states that a laboratory origin has not been established, while the best-supported hypothesis remains zoonotic spillover. It also notes that SAGO said a laboratory-related accident could neither be confirmed nor ruled out because key biosafety and staff-health records from Wuhan laboratories were unavailable.