An acrimonious debate about covid’s origins will rumble on

WHERE DIDSARS-CoV-2 covid-19 come from? You might imagine that the would be a matter for science. Instead it has become embroiled in acrimony, politics and, at times, conspiracy theory.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 , 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 three-and-a-half year row.