The Covid lab leak theory just got even stronger

Two years in, there is no doubt the Covid pandemic began in the Chinese city of Wuhan. But there is also little doubt that the bat carrying the progenitor of the virus lived somewhere else.

Central to the mystery of Covid’s origin is how a virus normally found in horseshoe bats in caves in the far south of China or south-east Asia turned up in a city a thousand miles north. New evidence suggests that part of the answer might lie in Laos.

The search for viruses closely related to Sars-CoV-2 took a new turn in September when a team of French and Laotian scientists found one in a horseshoe bat living in a cave in the west Laotian province of Vientiane. Other related viruses had been found in Cambodia, Thailand, Japan and elsewhere in China, but this one, Banal-52, was different. For the first time since the pandemic began, this was a virus genetically closer to the human Sars-CoV-2 virus than one called RaTG13, collected in southern Yunnan in 2013.