Impact of influenza vaccination on GP-diagnosed COVID-19 and all-cause mortality: a Dutch cohort study.
Arjan van LaakRuud VerheesJ André KnottnerusMariëtte HooiveldBjorn WinkensGeert Jan DinantPublished in: BMJ open (2022)
Our hypothesis of a possibly negative association between influenza vaccination in 2019 and GP-diagnosed COVID-19 was not confirmed as we found a slightly positive association. A slightly protective effect on all-cause mortality was found after influenza vaccination, possibly by a wider, overall protective effect on health. Future research designs should include test-confirmed COVID-19 cases and controls, adjustments for behavioural, socioeconomic and ethnic factors and validated cause-specific mortality cases.