BNT162b2 mRNA COVID-19 Vaccine Effectiveness in the Prevention of SARS-CoV-2 Infection and Symptomatic Disease in Five-Month Follow-Up: A Retrospective Cohort Study
Francesco Paolo Bianchi, Silvio Tafuri, Giovanni Migliore, Luigi Vimercati, Andrea Martinelli, Annamaria Lobifaro, Giusy Diella, Pasquale Stefanizzi, on behalf of the Control Room Working Group
Abstract
To combat the COVID-19 pandemic, a mass vaccination campaign was initiated in Italy on 27 December 2020. The vaccine available to immunize Italian healthcare workers (HCWs) was the BNT162b2 mRNA COVID-19 vaccine (Comirnaty). This study evaluated the effectiveness of the vaccine against documented SARS-CoV-2 infection and symptomatic diseases in the medium- to long-term. HCWs at Bari Policlinico University-Hospital (Italy) who completed the vaccination schedule were matched with HCWs who had refused vaccination; the two groups were followed-up for 5 months (January-May 2021). Vaccine effectiveness (VE) against infection was 97.7% (95.4-99.0%) at 14-34 days after the first dose, and 94.8% (87.0-97.8%), 83.0% (65.0-92.0%), and 81.0% (42.0-94.0%) at 14-41, 42-69, and >69 days, respectively, after the second dose. The estimated VE for documented symptomatic disease was 99.2% (96.4-99.8%) at 14-34 days after the first dose and 97.2% (90.3-99.2%), 85.0% (63.0-94.2%), and 88.0% (42.0-97.6%) at 14-41, 42-69, and >69 days, respectively, after the second dose. Efforts to increase vaccination rates should be strengthened, including mandatory vaccination for HCWs and greater incentives to increase vaccine acceptance by the general population.