It is nine months since the World Health Organisation (WHO) dismissed the possibility that the Covid 19 pandemic could have originated in a laboratory leak, calling it ‘extremely unlikely’. Since then, much scientific opinion has been moving in the direction that it is at least a possibility – especially given that the Wuhan Institute of Virology has been accused of engaging in ‘gain of function’ research into coronaviruses, involving manipulating the viruses into making them possibly more transmissible. Moreover, far from being rare, as the WHO intimated, the original SARS virus is known to have escaped from a laboratory on a couple of occasions.

But if Covid did get into the human population, how might it have escaped from the Wuhan lab? One possible answer lies in Taiwan, where a scientist working on Covid experiments at the Academia Sinica in Taipei has tested positive for the Delta variant of the SARS-CoV-2 virus after being bitten by a laboratory mouse on 19 November. No community transmission of Covid has been recorded in Taiwan for a month. The same worker had previously been bitten by a mouse at the laboratory a month earlier, but on that occasion tested negative.

It is proof – as if any were needed – that laboratory accidents can and do occur, and that it must be assumed that any microbe that is contained within a laboratory may at some stage escape into the outside human population outside, however strong are the protocols for containing it. Following this pandemic there will have to be a serious discussion as to what experiments should be allowed and which should not. The Wuhan research was targeted at helping the world cope with a future pandemic – but if such research turns out actually to have caused a pandemic, then it is a form of research that the world might well conclude it is better off doing without.

The other implication of the Taiwan incident is that it appears SARS-CoV-2 can be carried in animals other than bats – from which it is believed to have originated – and infect the human population via that route. That makes it much harder to imagine that we could ever contain Covid via restrictions on human movement alone. Rodents are quite capable of scurrying across borders however stringent quarantine is placed on human travellers.