Another way to look at the mink story. Does anyone remember the controversial flu gain of function (GOF) experiments with ferrets, where the virus was passaged to make it better at transmitting? Mink farms are a version of that experiment, except with millions of animals.

To unpack this a little bit. In the GOF experiments, flu mutants were passed from one ferret to another, from their respiratory tracts, to optimise their airborne transmissibility. What was particularly egregious here, was that a highly virulent flu strain was used, and passaged.

This meant taking a very dangerous virus, and making it also more transmissible, by passing it between an animal (ferrets) that is a great model for respiratory viruses of humans, because of the mode of transmission. Mink and ferrets both are susceptible to respiratory viruses.

SARS-Cov-2 is the virulent virus in this story, and mink the permissive host in which transmissibility can be optimised. By completing a cycle of 'natural passage' in a mink farm, and then coming back to humans, the virus is having a decent shot at becoming more transmissible.

This thread is not about whether the mutants found in the Danish farm are indeed 'vaccine escape' or anything like that, we don't know. But we have a natural experiment here, that very much looks like something that we have previously decided is far too dangerous to allow.

Caveat ( @JonathanKBall); it is not a one way street. Possible that passage in mink would make the virus less good at human transmission. But the fact it can complete a round in a mink farm and then come back, is cause for concern.