Six years after Covid-19 emerged in Wuhan, China, the origins of the pandemic remain uncertain, according to David Relman, a professor of medicine and microbiology at Stanford University. Both a natural spillover from wildlife markets and a lab accident in Wuhan are still considered viable possibilities.
Relman notes that risky work with bat coronaviruses, some supported by the US National Institutes of Health (NIH), was conducted in Wuhan. While this work involved creating chimeric viruses and testing their properties, published research does not show a plausible precursor to Covid-19.
Despite this, Relman's view is that a lab accident in Wuhan is the most plausible explanation for Covid-19. He cites the nature of the work, indications of Chinese researchers' knowledge about the Sars-CoV-2 virus before late December 2019, and thousands of negative tests from suspected animal reservoirs.
Relman advocates for an objective and transparent forensic investigation into Covid-19's origins with international engagement and accountability. He also calls for scientists to embrace responsibilities related to technical power and knowledge, and for political representatives to ensure balanced public discussion on the trade-offs of public health science.