Suspected adverse events following immunization against SARS-CoV2 in a university hospital in 2021: Observational study.

Aim: Vaccination against SARS-CoV2 has been proposed as a fundamental element for the control of the pandemic. This study aimed to describe the suspected adverse reactions (ADR) reported by vaccinated hospital workers.

Methods: A descriptive study of suspected ADR was conducted between January and March 2021. The suspected ADR were identified using a specifically designed electronic form and spontaneous reporting. Data were also collected regarding the characteristics of the professionals, vaccine administered, severity, and outcome of ADR.

Results: 8169 professionals received 2 doses of SARS-CoV2 vaccine (6672 Comirnaty® and 1497 Spikevax®) and 894 reports of suspected ADR were reported (762 for Comirnaty® and 132 for Spikevax®), resulting in a cumulative ADR incidence of 10.94% (95%CI: 10.27-11.62). The majority of ADR were reported only after the second dose, 497 (56.2%), while 211 (23.6%) were reported only after the first dose and 186 (21%) after both doses. The symptoms were mostly mild, did not require medical assistance, and disappeared within approximately 3 days. One hundred and seventeen professionals had a history of COVID-19 infection. These studies reported, statistically significant, more suspected ADR after the first dose (42.7%) than those with no history of COVID-19 (20.7%). Among professionals, more ADR occurred after the first dose with the Spikevax® vaccine (41.6%) than with the Comirnaty® vaccine (20.5%).

Conclusion: The majority of suspected ADR reported were described in the summary of product characteristics (SmPC). Professionals with a history of COVID-19 reported more suspected ADR after the first dose than did those without a history.