Randomised Vaccine Benefit

Lessons from an undisclosed NHS Trust

Back on 31st October I penned my 18th report entitled Assessing Vaccine Benefit: A Simulation Study Using In-hospital Death. This summarised a body of work I had undertaken in an attempt to understand a curious result; namely that vaccine benefit (in terms of reduced likelihood of in-hospital COVID death) could be established for some months but not others.  This simply did not make sense so I took 9,831 deaths occurring over the period 8/12/20 – 22/9/21 for an unknown NHS Trust and subject them to a simulation study.

Simulation studies are a handy technique whereby we deliberately mangle real world data, or synthesise data to understand what may or may not be going on in a complex situation. For this study I decided to try different ways of interfering with EPR data to see how this impacted on estimates of vaccine benefit. Thus, vaccination status was initially lagged by 1, 10, 100, 200 and 400 records with respect to COVID status within the EPR. Sliding records by just one case shoul…