BNT162b2 mRNA Covid-19 vaccine effectiveness in the prevention of SARS-CoV-2 infection: a preliminary report.

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