London, May 31 : The theory that Covid-19 is the result of a lab-leak should not be discounted, a top Chinese scientist has said. "You can always suspect anything. That's science. Don't rule out anything," George Fu Gao, was quoted as saying in an interview for the BBC Radio 4 podcast, 'Fever: The Hunt for Covid's Origin'. China has since the beginning dismissed any suggestion the disease may have originated in a Wuhan laboratory. Gao, who directed China's Center for Disease Control and Protection (CDC) when Covid first emerged in Wuhan, said a branch of the Chinese government had investigated the lab leak theory at the Wuhan Institute of Virology (WIV). The "lab was double-checked by the experts in the field". "I think their conclusion is that they are following all the protocols. They haven't found (an) wrongdoing," he said, in the first such acknowledgement that some kind of official investigation took place. "We really don't know where the virus came from a the question is still open," Gao told the BBC. More than two years after the pandemic that has infected over 763 million and claimed more than 6.9 million lives globally, the origins of Covid-19 remain unclear. It has been a political and scientific debate with scientists and politicians globally contending that the coronavirus jumped into people from bats, or have been leaked from a laboratory. In April, Gao said that the debate on how the Covid pandemic started has become "too sensitive and politicised", and that the true origins may "never be revealed". He noted that there is "no evidence" to show that the virus emerged from animals, Daily Mail reported. Gao, who stepped down in July 2022, said he did not see "anything unusual" until December 2019, a month before coronavirus was officially confirmed. "Even now, people think some animals are the host or reservoir," Daily Mail quoted Gao as saying. "Cut a long story short, there is no evidence which animals (were) where the virus comes (from)." /IANS