A team of World Health Organisation experts, which probed the origin of the novel coronavirus, said that it has "not yet" found the source of the deadly virus and called for further studies to find answers to questions, including allegations that it could have emanated from a bio lab, need to be addressed.
The report of the international team which visited the central Chinese city of Wuhan, where the virus was first reported in December 2019, from January 14 to February 10 was published on Tuesday.
"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," World Health Organisation Director-General Dr Tedros Adhanom Ghebreyesus said.
"It advances our understanding in important ways, while raising questions that will need to be addressed by further studies," Dr Tedros was quoted as saying by a WHO press release mailed to news outlets.
Significantly, Dr Tedros said the team has concluded that leak from the Wuhan Institute of Virology as alleged by former US president Donald Trump is the "least likely hypothesis" but it requires further probe.
"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," he said.
"However, I do not believe that this assessment was extensive enough. Further data and studies will be needed to reach more robust conclusions," he said.
"Although the team has concluded that a laboratory leak is the least likely hypothesis, this requires further investigation, potentially with additional missions involving specialist experts, which I am ready to deploy," Dr Tedros said.
According to Johns Hopkins University COVID-19 tracker, more than 127,814,400 confirmed cases have been reported across the world. It also reported that over 2,794,600 deaths have occurred globally due to the virus.
"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," Dr Tedros said.
He said the report which is eagerly awaited also raises further questions that will need to be addressed by further studies, as the team itself notes in the report.
The report presents a comprehensive review of the available data, suggesting that there was unrecognised transmission in December 2019, and possibly earlier, he said.
The team reports that the first detected case had symptom onset on the 8th of December 2019. But to understand the earliest cases, scientists would benefit from full access to data including biological samples from at least September 2019, he said.
"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," he said.
"I welcome the recommendations 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," the Who chief said.
The role of animal markets is still unclear, he said, adding that the team has confirmed that there was "widespread contamination with SARS-CoV-2 in the Huanan market in Wuhan, but could not determine the source of this contamination”.
"Again, I welcome the recommendations for further research, including a full analysis of the trade in animals and products in markets across Wuhan, particularly those linked to early human cases,” he said.
"I concur with the team's conclusion that farmers, suppliers and their contacts will need to be interviewed," he said.
The team also addressed the possibility that the virus was introduced to humans through the food chain.
Further study will be important to identify what role farmed wild animals may have played in introducing the virus to markets in Wuhan and beyond, he said.
"It is clear that we need more research across a range of areas, which will entail further field visits," he said.
The report came in the backdrop of US Secretary of State Antony Blinken's charge that Beijing has helped the WHO scientists to write the soon-to-be-released report on the origins of the coronavirus.
Blinken in an interview to CNN on Sunday expressed concern about the "methodology and the process" followed by the forthcoming WHO report on the origin of the coronavirus.
"There is a report coming out shortly by the World Health Organisation. There are real concerns about methodology and the process that went into that report including that fact that the government in Beijing has helped to write it. But let us see what comes out of that report," Blinken said.
He said there needs to be "accountability for the past" and "focus needs to be on building a stronger system for the future."
Reacting to Blinken's remarks, Chinese foreign ministry spokesman Zhao Lijian said on Monday that China will "never accept the groundless accusations and smearing on the epidemic related issues."
"The US has been making remarks on this. Is it doing so to try to impose pressure on the WHO expert group," he said.