US intelligence agencies are split on whether it came from a Chinese lab or animal-to-human contact.
US President Joe Biden has ordered intelligence officials to “redouble” efforts to investigate the origins of Covid-19, including the theory that it came from a laboratory in China.
He said the US intelligence community was split on whether it came from a lab accident or emerged from human contact with an infected animal.
Mr Biden asked the groups to report back to him within 90 days.
China has rejected the laboratory theory.
“Smear campaigns and blame shifting are making a comeback, and the conspiracy theory of ‘lab leak’ is resurfacing,” its embassy in the US said in a statement on Thursday.
Since it was first detected in the Chinese city of Wuhan in late 2019, more than 168 million cases of Covid-19 have been confirmed worldwide and at least 3.5 million deaths reported.
Authorities linked early Covid cases to a seafood market in Wuhan, leading scientists to theorise the virus first passed to humans from animals.
But recent US media reports have suggested growing evidence the virus could instead have emerged from a laboratory in China, perhaps through an accidental leak.
In what passes for relative transparency in the US government, the Biden administration has conceded the American intelligence community is split on Covid-19’s origins – it could be the lab or animal-to-human contact – and no-one is near certain about it.
That marks a big shift from the derision heaped on the lab theory by many in the media and politics last year, when Donald Trump, Secretary of State Mike Pompeo, Senator Tom Cotton and others floated the idea.
Mr Trump and Mr Pompeo didn’t help the situation, however, as they were coy about the grounds for their suspicion. And their theories floating alongside more far-fetched ones, such as that the disease was manufactured as a bioweapon in a Chinese lab. That possibility still seems highly unlikely.
The public may never know the full truth about the virus’ origins, particularly if China continues to be uncooperative. Mr Biden is pledging a full investigation, however, and if the US finds conclusive evidence of a lab leak, it will mean more than just a few prominent figures having to eat crow and re-evaluate their trust in authoritative “conclusions”. It could place very real strain on US-China relations for years to come.
In a statement on Wednesday, President Biden said he had asked for a report on the origins of Covid-19 after taking office, “including whether it emerged from human contact with an infected animal or from a laboratory accident”.
On receiving it this month, he asked for “additional follow-up”.
Mr Biden said the majority of the intelligence community had “coalesced” around those two scenarios, but “do not believe there is sufficient information to assess one to be more likely than the other”.
The president has now asked agencies to “redouble their efforts to collect and analyse information that could bring us closer to a definitive conclusion”.
He concluded by saying the US would “keep working with like-minded partners around the world to press China to participate in a full, transparent, evidence-based international investigation”.
Beijing has previously suggested Covid-19 could have come from a US laboratory instead.
In its statement, the Chinese embassy said it supported a full investigation into “some secretive bases and biological laboratories all over the world”.
A spokesman for China’s foreign ministry on Thursday hit out at the “dark history” of the US intelligence community, and said the Biden administration’s “motive and purposes” were clear.
Mr Biden’s statement came as CNN reported that the president’s administration this spring shut down a state department investigation into whether the virus could have leaked from a Wuhan lab, deeming the probe an ineffective use of resources.
Speculation about the Wuhan Institute of Virology – one of China’s top virus research labs – began last year and was propagated by former US President Donald Trump.
In April 2020, US State Department cables came to light that showed embassy officials were worried about biosecurity at the lab.
The leak allegations were widely dismissed as a fringe conspiracy theory.
Earlier this year, the World Health Organization (WHO) issued a report written jointly with Chinese scientists on the origins of Covid-19 which said the chances of it having started in a lab were “extremely unlikely”.
It said the virus had probably jumped from bats to humans via another intermediary animal, but more research was needed.
However, questions have persisted and recent reports attributed to US intelligence sources say three members of the Wuhan Institute of Virology were admitted to hospital in November 2019, several weeks before China acknowledged the first case of the new disease in the community.
Anthony Fauci, President Biden’s chief medical adviser, has maintained he believes the virus was passed from animals to humans, though he conceded this month he was no longer confident Covid-19 had developed naturally.
Mr Biden’s statement came the day after Xavier Becerra, US secretary for health and human services, urged the WHO to ensure a “transparent” investigation into the virus’s origins.
“Phase 2 of the Covid origins study must be launched with terms of reference that are transparent, science-based and give international experts the independence to fully assess the source of the virus and the early days of the outbreak,” he said.
On Tuesday, Mr Trump sought to take credit in a statement to the New York Post. “To me it was obvious from the beginning but I was badly criticised, as usual,” he said. “Now they are all saying: ‘He was right.'”