The World Health Organization (WHO) was going to present on Tuesday the report on its mission in China to trace the origin of COVID, but its conclusions have been leaked in some international media. Even so, they are not far from those that unveiled two months ago before heading back and after less than three weeks of field work. There are many unsolved doubts, but it seems that the most likely hypothesis is that of the intermediary animal between the bat and humans.
In the draft obtained by the Associated Press and other outlets such as The Washington Post, the researchers list four scenarios in order of probability of occurrence of SARS-CoV-2. The first is the aforementioned transmission from the bat through another animal, which is listed as “highly probable”. Direct spread from bats to humans would be “likely” and infection through a food chain or frozen products sold in Chinese markets is “possible” but “unlikely”.
The only hypothesis ruled out as “extremely unlikely” is that it had escaped from a Chinese laboratory. The experts determined that the Wuhan plants were well guarded and that these types of accidents are not common.
The mission, the document states, was never intended to identify the exact source of the virus, an effort that generally takes years. For example, it has not been possible to identify which exact species of bat is the natural reservoir of Ebola after more than 40 years of studies. However, in this case they assume that there is an intermediate species because “there are several decades of evolutionary distance between the bat virus and SARS-CoV-2, suggesting a missing link“It remains to be determined what that could be. animal, but among others, the pangolin or mink have been pointed out.