President Xi Jinping's communist administration has repeatedly denied the lab leak hypothesis, labelling it a smear campaign by 'anti-China' forces and insisting the virus emerged naturally.
Yet Beijing considered the theory credible enough to instigate its own formal probe, according to the former chief of the country's own public health watchdog, the equivalent of the UK Health Security Agency or Center for Disease Control and Prevention in the US.
Professor George Gao, who ran the organisation when the pandemic began towards the end of 2019, claimed the Wuhan Institute of Virology (WIV) was 'double-checked' by government-backed experts.
The BBC says Professor Gao's explosive revelation — shared with them — is the first acknowledgement of any internal inquiry taking place over the lab leak theory.
Discussing the possibility himself in a new podcast aimed to exploring the origins of the virus, he said: 'You can always suspect anything. That's science. Don't rule out anything.'
At first, the overwhelming opinion, shared by the world's leading experts, was that Covid crossed naturally from animals infected with a bat coronavirus.
But consensus over how the pandemic began three years ago has slowly started to shift.
The lab leak theory centres around the fact that the virus first emerged miles away from the WIV, where researchers were known to be working on coronaviruses found in bats.
Comment: It's likely that Zimbabwe has an idea that the US is up to something. And an increasing number of African nations are making it clear to they no longer have to accept the US and its relentless meddling: Leaders in Ghana, Zambia, slam US for 'undemocratic' meddling, amid VP Harris' tour of Africa