A World Health Organization draft report has found that Covid-19 likely originated in an animal and had been spreading a month or two before it came to notice in December of 2019, CNN reported.
According to the joint international team which studied the origins of the virus, the least likely source was a laboratory leak.
The final report of the WHO’s investigations is scheduled for release on Tuesday, but according to a draft version of the report obtained by CNN there was still no smoking gun and no evidence of the virus spreading any time before end- 2019.
WHO Draft Report Says Covid-19 Likely Originated In An Animal
The report has named four possible sources for the virus with the most likely scenario via an intermediate animal host, possibly a wild animal which was captured and raised on a farm.
The investigation however, has not identified the other animal infected by a bat, which is considered the virus’ most likely original source with the other animal transmitting it to a human. The report said the possible intermediate host of SARS-CoV-2 remained elusive.
The next likely scenario was direct transmission to humans from animals known as carriers of coronavirus, such as bats or pangolins. A possible but not probable transmission was from frozen or chilled food, with accidental laboratory release the least likely, according to the report.
According to Dr. Robert Redfield, former Director, US Centers for Disease Control and Prevention Director who spoke to CNN’s Dr. Sanjay Gupta his personal opinion was the virus was released from a lab.
According to the report, it was an extremely unlikely possibility given that there was no record of viruses related closely to SARS-CoV-2 in any laboratory prior to December 2019, or genomes that could combine to provide a SARS-CoV-2 genome. According to the report considering the possibilities, the pandemic’s alleged laboratory origin was extremely unlikely.
Independent researchers had maintained the position for months. Genomic testing of the virus indicated no evidence of it having been engineered in a lab, but passed naturally from animals, much like the SARS virus. The SARS virus had infected 8,000 people across the globe in 2002-2004.
The report said that frozen food was also not a likely source. It said there was no conclusive evidence for foodborne transmission of SARS-CoV-2. Furthermore, the possibility of cold-chain contamination with the virus from a reservoir also had low probability.
The role of Huanan seafood market in Wuhan was also not clear. It was possible the market was not the original source of the outbreak, but that the crowds that gathered at the densely packed market having a roof and open sewers might have amplified virus’ spread.
Sampling at the market did reveal the virus on surfaces, but it was not found in samples taken from animals. Also food sold at the market also did not have the virus and there was evidence of the virus circulating before the outbreak at the Huanan market and at other markets.
The Huanan market was associated with many of the early cases, but there were other markets similarly associated and some cases had no market association.
According to the report, transmission in the wider community in December could be responsible for cases that had no association with the Huanan market which, together with the presence of early cases that had no association with that market, could indicate that the Huanan market was not the outbreak’s original source.
The report said no firm conclusion as regards the role of the Huanan market could be currently drawn. No firm conclusion could also be drawn as to how the infection was introduced into the market.