At the heart of the contention is whether the virus could have emerged from a research accident involving a Wuhan laboratory studying bat coronaviruses – a hypothesis Beijing has staunchly denied, citing internal lab audits.

The earlier WHO group all but dismissed the theory, but Tedros and other scientists called for more rigorous evaluation of that and other hypotheses, including that the virus – like many others before it – had crossed over to humans via natural contact with wildlife.

But a question mark hangs over the extent to which international field research can continue in China, after Beijing in July rejected a WHO outline for further international fieldwork, balking at the inclusion of lab audits. Other nations, including the US, have called for an investigation into all hypotheses.

Meanwhile, two years have passed since the virus is believed to have jumped to people, making it potentially more difficult for scientists to trace clues like antibodies in the blood of animals or humans.

Against this backdrop, Sago is tasked with making recommendations to the WHO about the next steps for studies into the emergence of the virus.

‘Down the rabbit hole’: Covid-19 origins debate on Twitter takes a nasty turn

The group will also create a playbook for how future investigations into new pathogens are managed – widely seen as a bid to standardise a process that this time around was marred by delays before a WHO team could gain access to China.

The Sago members come from more than two dozen countries including the US, China, Russia, Kenya and Brazil, and fields such as virology, epidemiology, biosafety and animal health.

Sago will be chaired by medical virologist Marietjie Venter of South Africa’s University of Pretoria, with environment and infectious risks expert Jean-Claude Manuguerra of the Institut Pasteur in France as vice-chairman. Experts take part in a personal capacity, and Sago is envisioned as a permanent body.

The finalisation of the group come after a lengthy process of soliciting and vetting applications, with the WHO extending the deadline or reopening its call for experts several times since the original bid for applicants was put out in August.

‘May be our last chance’: Sago is WHO’s push to find Covid-19 origins

A standard two-week public comment period, designed to allow for feedback on representation or conflicts of interest, began in October after an initial list of 26 nominated experts was announced. The period ended not with a finalised list but with a call for more applicants, in particular in the social sciences and biosecurity.

The reopening of the application process followed criticisms from some scientists and proponents of examining the lab-leak theory that there was not enough expertise to plan for examination of that hypothesis. Some also raised concerns that several members of the controversial mission to Wuhan were part of the new group.

Two nominees were added to the list after that call, including Canadian biosafety inspector Normand Labbe.

China urges ‘objective, scientific’ focus for WHO’s next Covid-19 origins hunt

Dutch virologist Marion Koopmans, part of the original Wuhan mission team who was nominated for Sago alongside six other scientists who took part in that work, was not included in the final list issued by the WHO this week. The rest of the original experts remained the same, with the two additions.

Koopmans did not immediately respond to a request for comment.

Tuesday’s meeting was largely a procedural one and included scientific briefings and meetings with legal counsel and on compliance, risk management and ethics, according to the WHO.

“The group agreed to meet frequently and focus urgently on advising on the overarching framework to study the emergence of novel pathogens, as well as to rapidly undertake an assessment of the current understanding of the origins of … the virus that causes Covid-19,” the WHO said.