BNT162b2 mRNA COVID-19 Vaccine Effectiveness in the Prevention of SARS-CoV-2 Infection: A Preliminary Report.

ABSTRACT

In the preregistration trial, data on efficacy of BNT162b2 mRNA vaccine against SARS-CoV-2 infection were not collected. This study aimed to evaluate vaccine effectiveness (VE) against documented infection. Bari Policlinico University Hospital health care workers (HCWs) who completed the vaccination schedule were matched with HCWs who had refused vaccination. VE for documented infection was 61.9% (95% confidence interval [CI], 19.2%-82.0%) 14-20 days after first dose, 87.9% (95% CI, 51.7%-97.0%) 21-27 days after first dose, and 96.0% (95% CI, 82.2%-99.1%) 7 or more days after second dose. Unvaccinated HCWs remain a concern in the context of the pandemic emergency.