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Simpson's paradox in the interepretation of Covid fatality rates for vaccine effectiveness

Some people are looking at today's Public Health England report and concluding the Case Fatality Rate for Delta positive cases is much higher for vaccinated compared to unvaccinated. But this is an instance of Simpson's paradox as shown by this table:

In both age categories the rate among vaccinated is lower; but, when the numbers are aggregated the fatality rate for the vaccinated is much higher. And it is simply because a much greater proportion in the older age group (in which most deaths occur) are vaccinated compared to the younger age group. See a short video explanation of Simpson's paradox

However, it is worth noting, the following:

  • in the <50 age group there is little difference in fatality rate between the vaccinated and unvaccinated

  • the data that is completely missing is that relating to deaths (or serious adverse reactions) of vaccinated v unvaccinated people who were NOT classified as having the Covid. So there is no information on vaccine risks contained in this data.

In fact we have general concerns about the usefulness and validity of all the studies and data published so far into the effectivness and risks/benefits of Covid-19 vaccines. These concerns are discussed here:

So the above should certainly not be considered an argument in favour of the vaccine - n fact, we will shortly be producing a report about deaths and adverse reactions from the vaccine. However, it is important to call out misrepresentation of data on ‘both sides’ of the argument.

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