Background Vaccine effectiveness against COVID-19 needs to be assessed in diverse real-world population settings.Methods 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.Results 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 to 94%) effectiveness against new infection among the unvaccinated.Conclusion A satisfactory effectiveness of BNT162b2 after the second dose was suggested, but with possibly substantially lower effect before the second dose.Competing Interest StatementThe authors have declared no competing interest.Funding StatementThis study was supported by an internal grant for thematic collaboration initiatives at Lund University held by JB, and by Swedish Research Council (VR; grant number 2019-00198). FK is supported by grants from the Swedish Research Council and Governmental Funds for Clinical Research (ALF). The funders played no role in the design of the study, data collection or analysis, decision to publish, or preparation of the manuscript.Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Ethical approval was obtained from the Swedish Ethical Review Authority (2021-00059). As the study is register-based, individual participant consent was not necessary.All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesThe dataset used in the present study is hosted by Scania county council, Sweden. Legal and ethical restrictions prevent public sharing of the dataset. Data can be made available for collaborations upon request to interested researchers but would generally require a new ethical permission.
|Publication status||Published - 2021 Apr 21|