The Public Health England vaccine surveillance report for week 43 has dropped. Here’s the breakdown of official infections by vaccination status for the four weeks from 27 Sept. to 18 Oct.:
I had to make the graph myself, because they’re not publishing it anymore. Instead, we just get the tables, which they’ve festooned with hilarious disclaimers pleading that these numbers are “unadjusted,” by which they mean “inconvenient.”
On p. 20, they protest further:
Comparing case rates among vaccinated and unvaccinated populations should not be used to estimate vaccine effectiveness against COVID-19 infection. Vaccine effectiveness has been formally estimated from a number of different sources and is described on pages 4 to 7 in this report.
The case rates in the vaccinated and unvaccinated populations are unadjusted crude rates that do not take into account underlying statistical biases in the data.
There are likely to be systematic differences in who chooses to be tested and the COVID risk of people who are vaccinated.
• people who are fully vaccinated may be more health conscious and therefore more likely to get tested for COVID-19
• people who are fully vaccinated may engage in more social interactions because of their vaccination status, and therefore may have greater exposure to circulating COVID-19 infection
• people who are unvaccinated may have had past COVID-19 infection prior to the 4-week reporting period in the tables above, thereby artificially reducing the COVID-19 case rate in this population group, and making comparisons between the 2 groups less valid
It’s almost embarrassing to address these revealing, isolated demands for rigour:
1) The “different sources” which “formally estimate” efficacy “on pages 4 [actually, it’s 5] to 7 in this report” were all written months ago. So.
2) They really, really don’t want to argue that “people who are fully vaccinated” are “more health conscious.” That would suggest prior differences in the health of the vaccinated and unvaccinated populations, which would in turn suggest that worse outcomes in the unvaccinated are to some unknown degree the result of statistical confounding.
3) It is obvious to everyone that self-isolating Corona recluses are going to be found primarily on the vaccinated side of these breakdowns.
4) Yes, some of you have also postulated that higher rates of natural immunity among the unvaccinated are a major factor. What an embarrassment for the vaccinators, who are left to muse that populations with a partial rate of natural immunity are vastly more protected from infection than populations which have been fully vaccinated.