Our new article in the Journal of the Royal Society of Medicine examines the impact of vaccination on hospital admissions for Covid-19 in England during 2021. Covid-19 vaccination substantially reduced the risk of hospital admission, particularly in people who received three doses. We used data over a whole calendar year covering multiple variants of SARS-CoV-2, variable case rates and changing vaccine uptake.
This provides a population-level overview of the impact of vaccination that is not possible from studies over a shorter period. Using primary diagnosis of Covid-19 as the inclusion criteria increases the specificity of our study by excluding those co-incidentally Covid-19 positive but admitted for another reason. We excluded “ghost patients” that can bias the estimates of vaccine effectiveness.
We report a dose-dependent effect of vaccination, as well as waning of the effectiveness of each vaccination dose, highlighting the value of booster vaccinations. Our analysis supports an ongoing programme of booster vaccinations, especially in the elderly and risk groups.