UKHSA attempt to restrict use of calculations to measure how well vaccines are working
Public Health England has been replaced by the UK Health Security Agency, and the new agency has already made changes in what data is reported but moreover are trying to police what people do with it.
The data for numbers tested and positive by age has been stopped, as has the chart showing rates of infection by age in the vaccinated and unvaccinated cohorts. Thankfully the data on case numbers and the rates are still being reported.
The data are now presented with the following caveat:
“We present data on COVID-19 cases, hospitalisations and deaths by vaccination status. These raw data should not be used to estimate vaccine effectiveness as the data does not take into account inherent biases present such as differences in risk, behaviour and testing in the vaccinated and unvaccinated populations. Vaccine effectiveness is measured in other ways as detailed in the ‘Vaccine Effectiveness’ Section”
What the UKHSA fail to take into account is that, if their claims on vaccine effectiveness against infection were true, then either their database has overestimated the adult population by 7.5 million, or there have been so many undisclosed cases that deaths per case are comparable in the unvaccinated and vaccinated.
UKHSA is attempting to redefine a mathematical concept. The term for the percentage reduction in cases in a vaccinated cohort, compared to an unvaccinated cohort, is the vaccine effectiveness. A new word should not need inventing for this concept. The real world data may have inaccuracies in the numbers unvaccinated but the published literature is littered with its own biases. The CDC make clear that vaccine effectiveness is the term to use with real world data, and vaccine efficacy is reserved for calculations based on controlled studies. After all, if, as UKHSA claim, behavioural changes as a result of vaccination negate their benefit, then there needs to be a way of measuring that in the real world. Furthermore, UKHSA claim to be calculating vaccine effectiveness with other methods comparing the vaccinated proportion of the population coming forward for testing and testing positive. However, oddly, they have not reported on these results since May. There is room for critiquing the figure once it has been calculated but the ability to calculate the figure is not something that UKHSA have a right to police.