Effectiveness of BNT162b2 COVID-19 vaccine among healthcare workers of a large hospital, Milan, Italy
Safety and Health at Work
; 13:S220, 2022.
Article
in English
| EMBASE | ID: covidwho-1677150
ABSTRACT
Introduction:
Registration studies have shown high efficacy of BNT162b2 mRNA COVID-19 vaccine. We evaluated vaccine effectiveness (VE) of BNT162b2 mRNA COVID-19 vaccine in a cohort of healthcare workers (HCWs) of a large hospital in Milan, Lombardy, Italy. Material andMethods:
Follow-up started on 27 December 2020 (beginning of the vaccination campaign). HCWs without history of SARS-CoV-2 infection before the start date and with at least a nasopharyngeal test afterwards were included. Vaccination was treated as a time-dependent variable. For selected periods after vaccination we calculated incidence rate ratios (IRR) and 95% confidence intervals (CI) of infection with a Poisson regression model adjusted for gender, age, occupation, and 30-day periods, and then VE as (1 – IRR)x100 using unvaccinated person-time as reference. Databases were closed on 27 September 2021. The study was approved by the hospital’s ethics committee (Milano Area 2, Prot. No. 828_2021bis). Results andConclusions:
We included 3,809 HCWs, 131 still unvaccinated and 3,678 vaccinated (3,576 with two doses). We identified 134 infections (62% symptomatic). Adjusted VE was 77% (CI 43-91) from day 14 after the first vaccine dose and 87% (CI 79-92) at least 7 days after the second dose. After full vaccination schedule VE was 89% (CI 82-94) for symptomatic and 77% (CI 45-90) for asymptomatic infections. In conclusion, we found high effectiveness of BNT162b2 vaccine in reducing incidence of both symptomatic and asymptomatic infections. The follow-up is continuing to assess long-term effectiveness, also considering emerging SARS-CoV-2 variants.
tozinameran; adult; asymptomatic infection; comparative effectiveness; conference abstract; coronavirus disease 2019; dependent variable; drug therapy; female; follow up; gender; health care personnel; human; incidence; Italy; major clinical study; male; nonhuman; occupation; Poisson regression; professional standard; Severe acute respiratory syndrome coronavirus 2; vaccination
Full text:
Available
Collection:
Databases of international organizations
Database:
EMBASE
Type of study:
Experimental Studies
Topics:
Vaccines
Language:
English
Journal:
Safety and Health at Work
Year:
2022
Document Type:
Article
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