Scientists trying to zero in on the origins of the Covid-19 pandemic have recently filled in some critical blanks. The findings aren’t a smoking gun and might not convince some people who think the virus escaped from a laboratory in Wuhan, China. But they provide the sharpest view yet of the early days of the outbreak.
In two February preprint papers, first reported by the New York Times, researchers traced the spread of the SARS-CoV-2 virus, the pathogen that causes Covid-19, in 2019 in Wuhan. One study looked at initial infections…
