COVID-19 Vaccination and Asymptomatic Infection: Effect of BNT162b2 mRNA Vaccine on the Incidence of COVID-19 and Duration of Sick Leave Among Healthcare Workers

J Occup Environ Med. 2021 Dec 1;63(12):e868-e870. doi: 10.1097/JOM.0000000000002389.


Objective: To determine the incidence of COVID-19 and the duration of sick leave among asymptomatic healthcare workers (HCWs) after vaccination with BNT162b2.

Methods: From October 2020 to March 2021, we determined the incidence of COVID-19 in a cohort of 671 asymptomatic HCWs before and after the vaccination. We also analyzed the days required to obtain a negative RT-PCR result after infection.

Results: Prior to vaccination 105 (15.6%) HCWs were positive. Positive cases were reduced to 42 (7.5%) after the vaccination period (P < 0.0001). A negative RT-PCR was observed at the first control in 80% of vaccinated HCWs and only in 37% before vaccination.

Conclusions: Even in case of asymptomatic infection, vaccinated HCWs have a reduced incidence and a shorter period of sick leave than before vaccination, suggesting vaccination impacts on the sustainability of the health system and labor costs.

MeSH terms

  • Asymptomatic Infections
  • BNT162 Vaccine
  • COVID-19 Vaccines*
  • COVID-19*
  • Health Personnel
  • Humans
  • Incidence
  • SARS-CoV-2
  • Sick Leave
  • Vaccination
  • Vaccines, Synthetic


  • COVID-19 Vaccines
  • Vaccines, Synthetic
  • mRNA Vaccine
  • BNT162 Vaccine