This story features prominently in the BBC and other news sites this this morning. So how much weight should we give to it when evaluating the possibility that some form of useful herd immunity might never emerge?
Some clues can be found in the article itself: “So far, reinfection seems to be rare-there have been only a few examples out of more than 137 million cases” and only two known examples had more serious symptoms the second time round. So, unless many more similar cases emerge, we should give this story a weight of a bit more than one 37millionth, but not much more. To put this in numbers, we should weight it about 0.000000027. Even following the very best scientific protocols, it is easy to imagine random sequences of events that could explain this anomaly. Such event sequences might be highly improbable, but still be much probable likely than one thirty-seven millionth.