While calling for further studies and data on origin of SARS-CoV-2 virus, the World Health Organisation (WHO) has concluded that all hypotheses regarding the origin of SARS-CoV-2 — the virus responsible for the global COVID-19 pandemic, remain open.
The report of the international team on their Wuhan field visit, from 14 January to 10 February, was published today as WHO Director-General Dr Tedros Adhanom Ghebreyesus called for further studies.
The report stems from a Member State resolution adopted by consensus at the World Health Assembly in May 2020 and calling on WHO “to identify the zoonotic source of the virus and the route of introduction to the human population, including the possible role of intermediate hosts, including through efforts such as scientific and collaborative field missions.”
In remarks to Member States today, Dr Tedros, who received the full report on the weekend, thanked the team for their tireless work. He said it advances our understanding in important ways, while raising questions that will need to be addressed by further studies, as noted in the report.
“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,” said Dr Tedros.
“Finding the origin of a virus takes time and we owe it to the world to find the source so we can collectively take steps to reduce the risk of this happening again. No single research trip can provide all the answers.”
What WHO found in Wuhan, China
In its report available below, the experts noted the documented rapid increase in all-cause mortality 7 and pneumonia-specific deaths in the third week of 2020 indicated that virus transmission was widespread among the population of Wuhan by the first week of 2020.
“The steep increase in mortality that occurred one to two weeks later among the population in the Hubei Province outside Wuhan suggested that the epidemic in Wuhan preceded the spread in the rest of Hubei Province,” the report stated.
WHO-convened-global-study-of-origins-of-SARS-CoV-2-China-Part-joint-reportThe World Health Assembly resolution of May 2020, which was adopted by all Member States, cited a need “to identify the zoonotic source”. In July 2020 WHO sent a small team to China to plan a joint study comprising Chinese and independent international scientists. It was agreed that WHO would select the international scientists. The Terms of Reference for the Virus Origins Study were completed by fall 2020.
The team of scientists came from around the world: Australia, China, Denmark, Germany, Japan, Kenya, Netherlands, Qatar, the Russian Federation, the United Kingdom, the United States of America and Viet Nam. The joint international team comprised 17 Chinese and 17 international experts from 10 other countries as well as the World Organization for Animal Health (OIE); and WHO.
In an extensive exercise by 233 health institutions in Wuhan, some 76,253 records of cases of respiratory conditions in the two months of October and November before the outbreak in late 2019 were scrutinized clinically. Although 92 cases were considered to be compatible with SARS-CoV-2 infection after review, subsequent testing and further external multidisciplinary clinical review determined that none was in fact due to SARS-CoV-2 infection. Based on the analysis of this and other surveillance data, it is considered unlikely that any substantial transmission of SARS-CoV-2 infection was occurring in Wuhan during those two months.
The molecular epidemiology and bioinformatics working group examined the genomic data of viruses collected from animals. Evidence from surveys and targeted studies so far have shown that the coronaviruses most highly related to SARS-CoV-2 are found in bats and pangolins, suggesting that these mammals may be the reservoir of the virus that causes COVID-19. However, neither of the viruses identified so far from these mammalian species is sufficiently similar to SARS-CoV-2 to serve as its direct progenitor. In addition to these findings, the high susceptibility of mink and cats to SARS-CoV2 suggests that additional species of animals may act as a potential reservoir.