The latest UKHSA Vaccine Surveillance report was released Thursday, and its authors are now bending over backwards to keep their critics happy. Following a telling-off this week from the U.K. Statistics Authority, the UKHSA’s Head of Immunisation, Mary Ramsay (pictured above), published a blog post explaining what they’ve done to appease their detractors, while the report now states no fewer than four times, twice in bold typeface, that “these raw data should not be used to estimate vaccine effectiveness”. Ramsay grovels:
To make our data less susceptible to misinterpretation, the U.K. Health Security Agency has worked with the UK Statistics Authority to update some of the data tables and descriptions in the report, specifically around rates of infection in vaccinated and unvaccinated groups. In our commitment to transparent and clear data, we regularly review our publications to ensure they reflect the current situation within the pandemic, and we will continue to work with our partners at the statistics bodies, to ensure our reporting is as scientifically robust as possible.
As I noted last week, the UKHSA does not accept the criticism of its population estimates levelled by, among others, David Spiegelhalter, who declared that using them was “deeply untrustworthy and completely unacceptable”.
The agency instead takes the view that the problem is systemic biases in the data which mean it “should not be used” to estimate vaccine effectiveness. But as I have noted repeatedly, those biases just mean that the estimate will be of unadjusted vaccine effectiveness, which is a perfectly legitimate quantity to estimate and has its uses, particularly when looking at trends or when there is reason to think the biases may be relatively small. (For instance, a recent vaccine effectiveness study in California adjusted its raw data for 22 different factors but in almost all cases the adjustments were tiny.)
The UKHSA report itself correctly gives the definition of vaccine effectiveness: “Vaccine effectiveness is estimated by comparing rates of disease in vaccinated individuals to rates in unvaccinated individuals.” The U.S. CDC, likewise, states the definition as “the proportionate reduction in disease among the vaccinated group”. The CDC distinguishes “vaccine efficacy”, estimated from controlled studies, from “vaccine effectiveness”, which is used “when a study is carried out under typical field (that is, less than perfectly controlled) conditions”. It is therefore not appropriate for the UKHSA, a Government agency, to insist that its data “should not be used” to estimate vaccine effectiveness, which is a false statement and amounts to attempted Government censorship of scientific enquiry.
Infection Rates More than Twice as High in the Vaccinated, New UKHSA Data Shows, as Agency Dismisses Own Data as ‘Biased’. But Why No New VE Estimate Since May?Read More