As numerous relatives have (delightedly!) pointed out, due to my recent 50th birthday, I am now sufficiently old to be in the next or next-but-one group to be vaccinated. Turns out the advantage of getting old is not wisdom, which I don’t appear to be acquiring, but moving up the vaccine queue. So I am following all news of vaccinations with interest. Currently in the news is the suspension of use of the Oxford-AstraZeneca vaccine in a number of European countries including Germany. There is information on the basis of this decision in Germany here.
The part in the basis:
The number of these cases after vaccination with COVID-19 AstraZeneca is statistically significantly higher than the number of cerebral venous thromboses that normally occur in the unvaccinated population. For this purpose, an observed-versus-expected analysis was performed, comparing the number of cases expected without vaccination in a 14-day time window with the number of cases reported after approximately 1.6 million AstraZeneca vaccinations in Germany. About one case would have been expected, and seven cases had been reported.
worries me a bit. On the face of it looks scary, but they only compare the number of cases they find in vaccinated people with the expected number. This looks like it should be what you do, but it is well know that this can cause errors. In fact this is such a well known way of messing up that it has its own Wikipedia page.
The most colourful way of showing the problem was the subject of a blog post I wrote way back in 2012. See there for a description of the work on a dead salmon, that apparently can recognise human expressions. Here the problem may be (or may not, maybe they have considered this) that they are not just considering the rare thromboses they mention in the report. They are considering all possible adverse reactions, of which there must be thousands – sadly the number of ways of dying is very large. If you consider enough possible complications then one of them is bound to occur unusually often. Indeed if you compare the recently vaccinated with the general population for all possible complications, it would be statistically very weird if the vaccinated population did not show an excess number of complications for any complication.
Anyway, even if the risk is real (which it probably isn’t) I don’t care which vaccine I get. I am more than happy to take any vaccine I am given. They are very safe and COVID-19 kills.