This study found an association between vaccination with BNT162b2 in hospital employees and a decreased risk of symptomatic and asymptomatic infections with SARS-CoV-2. Limitations include the observational design; short follow-up time; small cohort size, which led to an inability to match the 2 groups and unequal follow-up; differential temporal risk during the surveillance; and that the group choosing not to be vaccinated may have been more prone to higher-risk behavior.

The unequal follow-up time and the latter 2 limitations may have biased the results in favor of vaccination.

Further research is needed to determine whether a reduction in risk of asymptomatic infection leads to reduced transmission.

Between December 17, 2020, and March 20, 2021, 5217 workers met vaccination criteria, 3052 (58.5%) received at least 1 BNT162b2 dose, and 2776 (53.2%) received 2 doses; 2165 (41.5%) were unvaccinated.

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