The Lynchpin of Retrospective Assessment of the Effectiveness of Influenza Vaccines
The case-negative study design
In Good News from the UK Scare Agency
We described the complicated alchemy used by the UK Health Scare Agency (UKHSA) to justify the use of influenza vaccines and produce implausible estimates of benefit, with a special focus on hospitalisations.
We cut through the description of overlapping data sources in the document, which were confusing, not representing the same individuals, and presumably there to impress and we got to the source of the claims.
Like in all models (yes, the claims in the end were based on a model as yet unpublished), the lynchpin, the most important variable to feed into the model apart from numbers of cases, is the estimates of vaccine effectiveness. Effectiveness means the capability of the vaccine(s) to prevent worrying outcomes, in this case, hospitalisations, as pointed out in the title of the UKHSA communique. The reason for spending a lot of our money on influenza vaccines is summed up in the term effectiveness. No or low effectiveness means we are wasting taxpayers’ money.
The problem with influenza and its vaccines is the positive bias in their use.