The World Health Organization has a leading theory regarding the origins of the COVID-19 pandemic but is considering three others in a forthcoming report, according to a recent AP article.
The most likely scenario is that the virus, which many scientists believe first appeared in bats, infected humans through an intermediary animal. Less likely is that bats infected humans directly.
The report also considers the possibility that the vaccine could have initially spread through contaminated frozen food products. The least likely scenario, although still possible, is that a laboratory such as the Wuhan Institute of Virology seeded the pandemic through an accident.
Shi Zhengli, who directs the Center for Emerging Infectious Diseases at the Wuhan Institute of Virology, has denied that the lab was the source of the SARS-CoV-2 pandemic. She also co-authored a study in Nature that concluded SARS-CoV-2 has 96.2% genomic similarity with the bat coronavirus RaTG13.
“At this point, there are no facts suggesting that there was a leak” from a laboratory, Vladimir Dedkov, an epidemiologist and deputy director of research at the St. Petersburg Pasteur Institute in Russia, told AP.
In early March, a group of scientists signed an open letter expressing their concerns that determining the pandemic’s origins would be “all but impossible” given the WHO researchers’ lack of access to substantive data.