Booster Vaccine Adverse Effects in HCWs

The study population is identical to the volunteer group of our previous study, who were health care workers of Szigetvár Hospital and received 2 doses of BNT162b2 mRNA (Pfizer/BioNTech, Comirnaty) vaccination between 27 January and 9 May 2021. The adverse reactions following the vaccinations were registered and the anti-SARS-CoV-2 spike Ig level was measured at 14, 30, 60, 90, 120, 150 and 180 days after the 2nd vaccination. Clinical data and details about adverse reactions were collected from medical records and dedicated questionnaire [5 (link)]. After the booster vaccination schedule became available, we contacted the volunteers again to participate in our follow-up study. Local and systemic solicited adverse reactions after the booster dose were recorded. This corresponds to the methodology used in our previous study. Based on the adverse reactions occurring within 7 days after vaccination, two groups were created: (i) symptomatic (side effects within 7 days after the 3rd dose) vs. asymptomatic (no reported side effects 7 days after the 3rd dose). We recorded the type of booster vaccine (heterologous vs. homologous schedules) and any COVID-19 positivity within 3 months following the booster dose.