Bob Wachter of UCSF had a very good thread on Twitter about vaccine rollouts the other day, and one of the good points he made was this one. We’re talking about treating very, very large populations, which means that you’re going to see the usual run of mortality and morbidity that you see across large samples. Specifically, if you take 10 million people and just wave your hand back and forth over their upper arms, in the next two months you would expect to see about 4,000 heart attacks. About 4,000 strokes. Over 9,000 new diagnoses of cancer. And about 14,000 of that ten million will die, out of usual all-causes mortality. No one would notice. That’s how many people die and get sick anyway.
But if you took those ten million people and gave them a new vaccine instead, there’s a real danger that those heart attacks, cancer diagnoses, and deaths will be attributed to the vaccine. I mean, if you reach a large enough population, you are literally going to have cases where someone gets the vaccine and drops dead the next day (just as they would have if they *didn’t* get the vaccine). It could prove difficult to convince that person’s friends and relatives of that lack of connection, though. Post hoc ergo propter hoc is one of the most powerful fallacies of human logic, and we’re not going to get rid of it any time soon. Especially when it comes to vaccines. The best we can do, I think, is to try to get the word out in advance. Let people know that such things are going to happen, because people get sick and die constantly in this world. The key will be whether they are getting sick or dying at a noticeably higher rate once they have been vaccinated.