China on Monday dismissed the possibility that the virus that caused COVID-19 leaked from a lab, after the CIA said it now favors the so-called lab leak theory over natural transmission. “It is extremely unlikely the pandemic was caused by a lab leak,

Beijing has never fully co-operated with international investigators, impeding the search for a definitive answer. But scientists continue their quest to establish the causes of a global health crisis that killed millions of people, caused trillions of dollars of economic damage and increased fears over the risks of virus research.