Reactogenicity of the BNT162b2 mRNA vaccine (Pfizer-BioNTech) against COVID-19 in workers of a tertiary hospital

To analyze the local and systemic reactions that appeared after the first and second dose of the BNT162b2 vaccine against COVID‑19 (Pfizer- BioNTech) in a sample of workers from a tertiary hospital, and to identify the  factors related to greater vaccine reactogenicity.

A self-administered questionnaire was used to interview 291 workers  from a tertiary hospital who received the BNT162b2 vaccine against COVID-19  between January and March 2021. The questionnaire included questions about  the sociodemographic variables of the participants, previous COVID-19  infection, and local and systemic reactions after the first and second dose of  the vaccine.

The most common adverse reaction was soreness at the injection site, which was reported more frequently after the first dose of the  vaccine. The systemic reactions evaluated were reported more frequently after the second dose of the vaccine. Women, younger adults, and  subjects with a prior COVID-19 infection reported increased reactogenicity. Furthermore, high reactogenicity after the first dose was found  to be related to a higher number of adverse reactions after the second dose of  the vaccine.

The distribution of reactogenicity in the present study is consistent with the data reported in previous studies on the BNT162b2 vaccine, especially in terms of its association with the participants'  characteristics. These findings could facilitate the identification of people at a  higher risk of developing high reactogenicity to the vaccine, thereby making it  possible to anticipate the appearance of adverse reactions and plan for their  treatment.