As focus shifts to the next phase of research on the origins of SARS-CoV-2, calls for data sharing and more rigorous studies intensify. John Zarocostas reports.

The publication on March 30, 2021, of a joint WHO–China study on the origins of SARS-CoV-2 has led to calls by the head of WHO for more rigorous studies.

“As far as WHO is concerned, all hypotheses remain on the table. This report is a very important beginning, but it is not the end. We have not yet found the source of the virus, and we must continue to follow the science and leave no stone unturned as we do”, declared Tedros Adhanom Ghebreyesus, WHO director-general.

The joint-team's assessment followed a 4-week visit to Wuhan in January and February. It ranked direct zoonotic spillover as “possible-to-likely”; introduction through an intermediate host as “likely-to-very likely”; introduction through cold or food chain products as “possible”; and introduction through a laboratory incident as “extremely unlikely”.

In remarks to WHO member states, Tedros made clear that he did not believe the assessment of a laboratory incident was extensive enough. “Further data and studies will be needed to reach more robust conclusions.” He also indicated that WHO expects more from China. “In my discussions with the team, they expressed the difficulties they encountered in accessing raw data. I expect future collaborative studies to include more timely and comprehensive data sharing.”

Tedros noted that the study suggests that unrecognised transmission occurred in December, 2019, and possibly earlier, and said that “scientists would benefit from full access to data including biological samples from at least September 2019”.

White House press secretary Jen Psaki said on March 30 that the WHO report “lacks crucial data, information, and access. It represents a partial and incomplete picture”.“There's a second stage in this process that we believe should be led by international and independent experts. They should have unfettered access to data. They should be able to ask questions of people who are on the ground at this point in time, and that's a step the WHO could take”, Psaki added, echoing concerns reflected in a joint statement issued by 14 countries including Australia, Canada, Denmark, Israel, Japan, Norway, South Korea, the UK, and the USA.

Similarly, an EU statement noted the limited availability of early samples and related data, but considers the study ”as a helpful first step”. The EU said further work on the origins of SARS-CoV-2 and its introduction into the human population “will require further timely access to all relevant locations and to all relevant human, animal and environmental data from the first identified COVID-19 cases and picked up by surveillance systems, as well as serologic testing and blood samples”.

Health diplomats speaking on condition of anonymity said that senior Chinese officials viewed the statements as an attempt to politicise the study. However, the same sources noted that the Chinese Government had leaned on its experts to promote certain positions.

China Daily reported that at a news conference on March 31, Liang Wannian, head of the Chinese team, said that ”the hypothesis that China did not share raw data is unfounded”. “The report will withstand the test of history”, he said.

“Even though countries have been at odds with each other and despite the challenges, it is important not to devalue the international scientific technical collaboration that has taken place [since the outbreak] and is continuing in making advances in understanding SARS-CoV-2 and COVID-19, including in the recent WHO-led mission to Wuhan”, David Heymann, professor of infectious disease epidemiology at the London School of Hygiene & Tropical Medicine, London, UK, toldThe Lancet.

Likewise, Peter Daszak, president of EcoHealth Alliance and a member of the international team, told journalists the report is a testament to how even under very difficult political circumstances “countries can come together to focus on the origins of emerging diseases”.

Another member of the team, John Watson, head of respiratory diseases at Public Health England, UK, said “to take this further and get closer to that answer, we need to be able to continue that collaboration, that dialogue with our colleagues in China”.

Peter Ben Embarek, WHO scientist for food safety and zoonosis, and team leader of the Wuhan mission, when asked about future studies, toldThe Lancet, in particular, he recommended to “follow up on the identified farmed wild animal products suppliers to the Huanan market and study their animal, environmental and human environment as well as possible products supplied to the market in late 2019 and possibly still present in different warehouses”.

Embarek also called for a project to test the samples stored in the Wuhan and other relevant blood banks, as well as continued and broadened sampling of relevant bat species and other wild animals.