Underreporting of Adverse Events Following COVID-19 Vaccination Among Healthcare Professionals in Poland: Potential Implications for Vaccine Hesitancy.

This study aimed to assess the prevalence and reporting rate of adverse events following immunization (AEFIs) among healthcare professionals (HCPs) and students of health-related disciplines after COVID-19 vaccination. It was conducted at the beginning of the vaccination campaign in Poland (February 2021), when vaccines were only available to limited groups of recipients, mainly those related to healthcare. Questionnaires were distributed among HCPs in the Pomeranian voivodeship (N = 1063) and students at the Medical University of Gdańsk (N = 1506). The primary objective was to compare respondents' self-reported AEFI notifications with official reports published by the National Sanitary Inspectorate. A total of 240 participants declared having reported at least one AEFI, whereas official reports from the same period indicated that only 194 individuals had reported AEFIs in the entire voivodeship. This translates into significant differences in notification rates (14.9% and 0.09%, respectively). A detailed breakdown into local and systemic AEFIs also revealed significant discrepancies with official reports (850 vs. 329 and 1137 vs. 46, respectively). The most common reasons for not reporting were managing the symptoms on one's own and perceiving the symptoms as not severe enough to report. Underreporting of AEFIs is an issue that requires attention from both the scientific community and public health authorities, as it may hinder reliable vaccine safety assessment and contribute to increased vaccine hesitancy.