Björk J, Inghammar M, Moghaddassi M, Rasmussen M, Malmqvist U, Kahn F
Infect Dis (Lond) - (-) 1-6 [2021-09-29; online 2021-09-29]
Vaccine effectiveness against COVID-19 needs to be assessed in diverse real-world population settings. A cohort study of 805,741 residents in Skåne county, Southern Sweden, aged 18-64 years, of whom 26,587 received at least one dose of the BNT162b2 vaccine. Incidence rates of COVID-19 were estimated in sex- and age-adjusted analysis and stratified in two-week periods with substantial community spread of the disease. The estimated vaccine effectiveness in preventing infection ≥7 days after second dose was 86% (95% CI 72-94%) but only 42% (95% CI 14-63%) ≥14 days after a single dose. No difference in vaccine effectiveness was observed between females and males. Having a prior positive test was associated with 91% (95% CI 85-94%) effectiveness against new infection among the unvaccinated. A satisfactory effectiveness of BNT162b2 after the second dose was suggested, but with possibly substantially lower effect before the second dose.