Members of a World Health Organization-led team looking for clues about the origins of COVID-19 held a briefing on Tuesday after nearly a month of meetings and site visits in the Chinese city of Wuhan, where the disease was first identified.
A member of the WHO-China joint study team, Liang Wannian, said that there is no evidence of transmission of the novel coronavirus before December 2019 in Wuhan.
The WHO team recommended that more studies are required to identify the source of Covid-19 spread in the world.
Another World Health Organisation expert said the coronavirus is unlikely to have leaked from a Chinese lab and most probably jumped to humans via an intermediary species.
WHO food safety and animal diseases expert Peter Ben Embarek made the assessment in a summation Tuesday of a WHO team's investigation into the possible origins of the coronavirus in the central Chinese city of Wuhan.
Embarek said that cold chain transmission of the virus is a possibility and warrants further investigation.
'Cold chain' refers to the transport and trade of frozen food. China has pushed the idea that the virus can be transmitted by frozen food and has repeatedly announced findings of coronavirus traces on imported food packaging.
"We know the virus can survive in conditions that are found in these cold, frozen environments, but we don't really understand if the virus can transmit to humans" or under which conditions, he told the briefing.
He said that work to identify the origins of the coronavirus points to a natural reservoir in bats, but it is unlikely that they were in Wuhan.
The WHO team that includes experts from 10 nations arrived in Wuhan on January 14 and after two weeks of quarantine, visited key sites like the Huanan seafood market, the location of the first known cluster of infections, as well as the Wuhan Institute of Virology, which has been involved in coronavirus research.
While the virus is widely believed to have originated from an animal source and spread to humans through an intermediary, the WHO team emphasised on studying the possibility of the transmission of the virus through frozen food, along with other possibilities.
Another team member, infectious disease expert Dominic Dwyer, said it would probably take years to fully understand the origins of COVID-19.
The first clusters of COVID-19 were detected in Wuhan in late 2019, prompting the government to put the city of 11 million under a strict 76-day lockdown.
(With inputs from agencies)