Chinese authorities have consistently denied that COVID-19 originally leaked from a laboratory in Wuhan. But virologist George Gao, who was then head of the Chinese Institute for Disease Control, is not so sure.
"You can always suspect everything. That's science. Don't rule anything out," he said in an interview with BBC Radio 4. The Chinese government may have taken the theory of the lab leak more seriously than it wanted to make it out to be, says Gao.