A team of international scientists tasked with understanding how the coronavirus pandemic began released their first report on Thursday, saying that all hypothesis remain on the table, including a possible laboratory incident.
The 27-member scientific advisory group convened by the World Health Organization said available data suggests the virus jumped from animals to humans but gaps in “key pieces of data” meant a complete understanding of the pandemic’s origins could not be established.
The team, called the Scientific Advisory Group for the Origins of Novel Pathogens (SAGO), was formed last year to recommend further areas of study to better understand the pandemic’s origins and as well as the emergence of future pathogens.
“Studying origins of any novel pathogen or pandemic is incredibly difficult,” said Dr. Maria Van Kerkhove, WHO’s Covid-19 technical lead for its Health Emergencies Program. “There is a lot more work that needs to be done, in China and elsewhere.”
Here are key takeaways from the report.
Current data suggests a zoonotic origin of SARS-CoV-2 – which means the virus originated in animals and jumped to humans.
The most closely genetically related viruses were found to be beta coronaviruses identified in bats in China and Laos, according to SAGO.
“However, so far neither the virus progenitors nor the natural/intermediate hosts or spill-over event to humans have been identified,” the report said.
The group pointed to published surveys of animals sold at the Huanan Seafood Market in Wuhan, where the virus was first identified.
Between 2017 and 2019, the survey showed that several species known to be susceptible to SARS-CoV-2, such as racoon dogs and red foxes, were present in the market. But those animals were not sampled in the studies presented to the team by invited Chinese scientists.
SAGO said further information about studies into the testing of these animals, as well as tracing back to source farms and serologic investigations into people who farmed and sold or traded the animals have been requested.
The seafood market
Another area the group identified for further study is the Huanan Seafood Market in Wuhan, which investigations suggest “played an important role early in the amplification of the pandemic.”
Several of the patients first detected in December 2019 had a link to the market, and environmental samples from the market tested positive for the virus, the report said.
However, once again, big gaps remain.
It is not clear how the source of the virus was introduced to the market and where the initial spill over to humans occurred, the group said, adding that follow-up studies have not been completed.
“There is a need to examine environmental samples collected from specific stalls and drains at the market in January 2020 that tested positive for SARS-CoV-2 in areas known to have sold live animals,” SAGO said.
“Other essential studies include detailed mapping of upmarket trade of wild/domestic animals sold in Wuhan City and Hubei Province and clinical history and seroprevalence of SARS-CoV-2 antibodies in humans and animals from the source farms of animals sold at Wuhan markets,” the report said.
The lab-leak theory
SAGO’s preliminary report said it “remains important to consider all reasonable scientific data” to evaluate the possibility that Covid-19 spilled into the human population through a laboratory incident.
However, the group said there “has not been any new data made available” to evaluate this theory and recommended further investigation “into this and all other possible pathways.”
Essentially, because lab leaks have happened in the past and there is no new data available, the group said this theory cannot be ruled out.
Three members from Russia, Brazil and China objected to this recommendation, “due to the fact that from their viewpoint, there is no new scientific evidence to question the conclusion” of a WHO report from March 2021 that describes the lab leak theory as “extremely unlikely.”
That report came under intense scrutiny, with the US government expressing concerns over its independence and credibility and WHO Director-General Tedros Adhanom Ghebreyesus admitting that its authors had problems with data access in China.
Nonetheless, experts have roundly condemned the theory of a laboratory origin for the virus, saying that there’s no proof of such origins or of a leak.
‘We do not yet have the answers’
The team also had access to unpublished blood samples from 40,000 donors in Wuhan between September and December 2019, and reported to have been tested for Covid antibodies. Their samples could contain crucial signs of the first antibodies made by humans against the disease.
According to the report, more than 200 samples initially tested positive for the antibodies but when tested again were not found to be positive. SAGO said it has requested further information on the data and methods used to analyze the samples.
Similarly, the group recommended further study of 76,000 Covid patients identified in the months before the initial outbreak in Wuhan in December 2019 and who were later discounted.
SAGO also said it supports further investigations in any part of the world where there is “firm evidence” of coronavirus in humans before the recognized outbreak.
The preliminary report was based on studies reviewed by SAGO, which was only able to assess information that was made available to them through published reports or presentations from invited scientists.
On Thursday, WHO Director-General Tedros said it has been two-and-a-half years since Covid-19 was first identified but “we do not yet have the answers as to where it came from or how it entered the human population.”
He urged the importance of scientific work being kept separate from politics.
“The only way this scientific work can progress successfully is with full collaboration from all countries, including China, where the first cases of SARS-CoV-2 were reported,” he said.
CNN’s Katherine Dillinger contributed reporting.