The theory that SARS-CoV-2, the virus responsible for COVID-19, could have come from a Wuhan laboratory has once again resurfaced after a top Chinese scientist openly addressed the idea in what seemed to be the first admission that the Chinese government did consider its possibility at one point.

Professor George Gao, the former head of China's Center for Disease Control and Prevention (CDC), disclosed in the BBC Radio 4 podcast "Fever: The Hunt for COVID's Origin" that the Chinese government did not really dismiss the idea that the virus could have come from a laboratory in Wuhan.

"The government organized something," Gao said before noting that the Chinese CDC was not tapped to get involved. He then confirmed that authorities investigated the Wuhan Institute of Virology, one of China's top national laboratories, because it was known to be studying coronaviruses for years.

"That lab was double-checked by the experts in the field," Gao was quoted as saying by the BBC. "You can always suspect anything. That's science. Don't rule out anything."

The internationally respected virologist admitted that he did not see the official result of the investigation, but he heard that the lab received a clean bill of health.

"I think their conclusion is that they are following all the protocols. They haven't found [any] wrongdoing," he said.

Gao was at the forefront of China's response to the public health emergency since he served as the CDC chief until July 2022. He is now the vice president of the National Natural Science Foundation of China, per The Guardian.

The COVID-19 pandemic was officially declared over by the World Health Organization (WHO) on May 5. However, the origins of the virus continue to baffle scientists.

The general notion was that SARS-CoV-2 came from bats. However, there's no evidence to prove this yet. It's also unclear how the virus was transmitted to humans and how it evolved into a zoonotic disease.

In March 2021, WHO researchers released a report after conducting a research visit to Wuhan, saying that the lab leak theory was "extremely unlikely," according to The Guardian.

The Chinese government has openly dismissed the speculation that SARS-CoV-2 was leaked from one of the country's laboratories, declaring such theory "false and erroneous."

Gao reiterated that even China is clueless about where the virus really started or came from. "We really don't know where the virus came from... the question is still open," he said.