Now we know what those leading scientists really thought. Emails exchanged between them after a conference call on 1 February 2020, and only now forced into the public domain by Republicans in the US Congress, show that they not only thought the virus might have leaked from a lab, but they also went much further in private. They thought the genome sequence of the new virus showed a strong likelihood of having been deliberately manipulated or accidentally mutated in the lab. Yet later they drafted an article for a scientific journal arguing that the suggestion not just of a manipulated virus, but even of an accidental spill, could be confidently dismissed and was a crackpot conspiracy theory…

The emails unveiled this week reveal no good scientific reason at all for why these leading virologists changed their minds and became deniers rather than believers in even the remote possibility of a lab leak, all in just a few days in February 2020. No new data, no new arguments. But they do very clearly reveal a blatant political reason for the volte-face. Speculating about a lab leak, said Ron Fouchier, a Dutch researcher, might ‘do unnecessary harm to science in general and science in China in particular’. Francis Collins was pithier, worrying about ‘doing great potential harm to science and international harmony’. Contradicting Donald Trump, protecting science’s reputation at all costs and keeping in with those who dole out large grants are pretty strong incentives to change one’s mind.