An acrimonious debate about covid’s origins will rumble on
New diseases in people almost always come from close contact between human populations and animals. A “spillover" happens when viruses from an animal species jump into humans and then go on to wreak havoc. But the idea that SARS-CoV-2, the virus that causes covid-19, instead leaked from a Chinese research laboratory has persisted since the earliest days of the pandemic. Though this theory has rested largely on rumours and circumstantial evidence, it has nevertheless set the stage for a bitter…