A health expert affiliated with the World Health Organization has called on the US to share any intelligence it has about the origins of the coronavirus outbreak with the WHO and the scientific community. Last week the Wall Street Journal cited US intelligence agencies who said they were told that three unnamed members of staff at a lab in the Chinese city of Wuhan were sick enough to go hospital in November 2019 with Covid-like symptoms. US intelligence chiefs later stressed they did not know how the virus was transmitted initially, but that they had two theories: either it emerged naturally from human contact with infected animals, or it was a laboratory accident. Speaking to BBC Radio 4’s The World This Weekend, Dr Dale Fisher said the theory that the virus leaked from a laboratory was “not off the table”, but remained “unverified”. Fisher, chair of the Global Outbreak Alert and Response Network, which is coordinated by the WHO, urged the US to share any intelligence it had. “The Wall Street Journal is not really the way to share science,” he said. An on-the-ground investigation by WHO experts earlier this year concluded that it was “extremely unlikely” that the pandemic began with a laboratory incident. But the terms of reference for their mission, agreed with China, were limited to studying the potential animal origins of the outbreak. The broad consensus among scientific experts remains that the most likely explanation is that Covid-19 jumped to humans from an animal host in a natural event. Nevertheless, some experts have called for the lab leak theory – once dismissed as a conspiracy peddled by Donald Trump – to be looked at further. Referring to the WHO’s visit earlier this year, Fisher said: “We believe that all the laboratory workers have had serology [tests] done and all those antibody tests were negative and that was part of the reason why the risk was downplayed.” Dr Tedros Adhanom Ghebreyesus, director general of the WHO, said he did not believe the initial report was extensive enough and called for more research, adding that all hypotheses as to the origins of the virus that causes Covid-19 “remain on the table”. Fisher urged the WHO to set out its plans for further investigation. He said: “People really haven’t heard anything since the February mission was done and therefore people think they’ve stopped looking for the origins, which is far from the truth – it’s only really just begun.” The UK vaccines minister, Nadhim Zahawi, said the WHO must be allowed to fully investigate, telling Sky News: “I think it’s really important that the WHO is allowed to conduct its investigation unencumbered into the origins of this pandemic and that we should leave no stone unturned.” Fisher, who took part in a WHO mission in 2020, suggested that China’s secrecy about the origins of the virus could be driven by fears of compensation claims. He said: “Any country that found any Covid-19 in its borders before the outbreak started would suddenly clam up. This is why I would argue that diplomacy is the way forward with this, creating a no-blame culture. The only way you really can get to the bottom of this is just to say: ‘Look, there’s no penalties, we just need to sort this out.’”