Even after a year and a half of SARS-CoV-2 virus invading the world, the global scientific community is yet to ascertain how the virus surfaced in Wuhan in China and became a pandemic.
A report by the World Health Organization (WHO) international study team of experts, who went to Wuhan from 14 January -10 February 2021, could not ascertain the origin of virus. The visit was based on a WHO resolution, adopted by consensus at the World Health Assembly in May 2020, to identify the zoonotic (animal to human) source of the virus and the route of introduction to the human population, including the possible role of intermediate hosts.
The report confirmed that there was widespread contamination with SARS-CoV-2 in the Huanan market in Wuhan city of China but could not determine the source of this contamination.
The report was made after a comprehensive review of available data, suggesting that there was unrecognised transmission in December 2019, and possibly earlier. The first detected case had symptom onset on the 8 December 2019. But to understand the earliest cases, scientists need to access data including biological samples from at least September 2019, suggested the experts.
"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. 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, said WHO Director-General Dr Tedros Adhanom Ghebreyesus, while releasing the full report.
The report recommended for further studies to understand the earliest human cases and clusters, to trace the animals sold at markets in and around Wuhan, and to better understand the range of potential animal hosts and intermediaries.
Farmers, suppliers and their contacts will need to be interviewed. Possibly, the virus was introduced to humans through the food chain. The team also visited several laboratories in Wuhan and considered the possibility that the virus entered the human population as a result of a laboratory incident. However, the team has concluded that a laboratory leak is the least likely hypothesis and requires further investigation.