WHO team begins COVID-19 origin investigation

A WHO-led international mission has begun investigations in China to try to establish the origin of SARS-CoV-2. John Zarocostas reports on its activities.

With new infections of COVID-19 still spreading rapidly, and health systems stretched to their limits, public interest is focused on the WHO-led international mission in China to investigate the origin of the virus that initiated the pandemic.

“No one should be in any doubt that this is a scientific exercise”, Tedros Adhanom Ghebreyesus, WHO director-general, told health ministers on Jan 18, 2021, a few days after the mission had arrived in China, in a clear move to shield WHO's work from the political tensions that have marred the pandemic response over Beijing's initial lack of transparency in the early days of the outbreak centred in Wuhan.

During the World Health Assembly in May, 2020, health ministers passed a resolution that requested WHO to work with partners and countries “to identify the zoonotic source of the virus and the route of introduction to the human population, including the possible role of intermediate hosts”.

Peter Ben Embarek, WHO scientist for food safety and zoonosis, and team leader of the mission, noted in mid-January, “it's important to understand the origin of the virus for three reasons. One is if we find the source and if it's still out there, we can prevent future reintroduction of the same virus into the human population. Second, if we understand how this one jumped from bats origin into humans, we can perhaps prevent similar events in the future. Third, if we can find the virus, what it looked like before it jumped to the human population, we could potentially be in a better position to develop more efficient treatments and vaccines for this disease”.

The investigative team consists of ten international experts and includes epidemiologists, animal and human disease experts, veterinarians, medical doctors, and virologists, from ten countries, and also five WHO experts, two representatives from the Food and Agriculture Organization, and two from the World Organisation for Animal Health (OIE).

The international experts tapped by WHO include John Watson, head of respiratory diseases at Public Health England, UK; Peter Daszak, president of EcoHealth Alliance, USA; Dominic Dwyer, Professor of Medicine at The University of Sydney, and member of the team that grew live SARS-CoV-2 in February, 2020; and Marion Koopmans, head of the Erasmus MC Department of ViroScience, Netherlands.

14 members of the team have been deployed in China, including eight international experts, five WHO experts, and one representative from OIE (Keith Hamilton, head of preparedness and resilience). The rest are working remotely, WHO said.

In the first 2 weeks, the deployed team worked online with their Chinese counterparts from China's Center for Disease Control and Prevention (CDC) and different ministries and research centres, and in the remaining 2 weeks will be able to move freely and visit sites that are important for their research.

This research will include investigating the Huanan market in Wuhan and trying to identify everything that went in and out of the market in late November and December, 2019, conducting interviews with some of the first identified COVID-19 patients, and visiting hospitals and laboratories (including the Wuhan Institute of Virology and Wuhan CDC laboratory) and other research facilities to review epidemiological, virological, and serological studies, and also look at biosafety, WHO officials said.

The team will also map supply chains at Huanan and other markets, test frozen sewage samples, and do other studies as appropriate, they said. The team is also expected to review hospital records for cases compatible with COVID-19 before December, 2019, and review disease trends for the months preceding the outbreak for any unusual patterns of illness.

“I don't think we will have clear answers after the initial mission, but we will be on the way, and hopefully in the coming months that will be completed by additional missions”, said Embarek.

David Heymann, professor of infectious disease epidemiology at the London School of Hygiene & Tropical Medicine, London, UK, however, told The Lancet that “it is unlikely that the WHO team working with Chinese investigators will be able to determine the origin of the pandemic—it is very difficult to do this retrospectively by identifying early cases and then proceeding with case-control studies to identify risk factors for infection. And what matters now is controlling the current outbreak and understanding how to better prevent such pandemics in the future”.

As seen from previous outbreaks, says WHO, “it can take years to find the origin of viruses that have made the zoonotic jump from animals to humans”.