SHANGHAI: Despite a high-profile visit to China by a team of international experts in January, the world is no closer to knowing the origins of Covid-19, according to one of the authors of an open letter calling for a new investigation into the pandemic.

“At this point we are no further advanced than we were a year ago,” said Nikolai Petrovsky, an expert in vaccines at Flinders University in Adelaide, Australia, and one of 26 global experts who signed the open letter, published yesterday.