AbstractBackgroundIn manufacturers’ trials, vaccination against COVID-19 proved to be safe and effective. The officially reported frequency of vaccine adverse events (VAEs) in Poland is lower than that declared by the manufacturers. The anti-vaccination activists questioned the trustworthiness of official data.ObjectivesThe aim was to explore the real-life prevalence of VAEs in general practice settings and the factors that may influence it.MethodsIn this pragmatic, mixed prospective and retrospective study, patients vaccinated against COVID-19 between May and October 2021 in three GP practices in Krakow, Poland, were enrolled. Their demographic (age, sex, level of education) and clinical data (weight and height, smoking status, history of allergies, COVID-19 and chronic diseases) were collected. Then, they were interviewed about VAEs they experienced.ResultsOut of 1530 patients invited to participate, 1051 (69%) agreed and were eligible for analyses. Only 8.8% did not report any VAE. Pain at the injection site was the most frequently reported reaction (800, 76.2%). The most prevalent systemic ones were excessive fatigue/lethargy (527, 50.6%), sleep/circadian rhythm disturbances (433, 41.6%) and headache (399, 38.3%). Fifty required medical assistance − 39 experienced presyncope (3.7%) and 11 loss of consciousness (1.1%). Only two others were hospitalised. Females, younger adults, those with higher education and with a history of COVID-19 reported systemic VAEs more frequently, while those who were older and obese were less likely to report local reactions.ConclusionAlthough more than 90% of patients vaccinated against COVID-19 in general practice settings may experience VAEs, in short-term observation, the vast majority are localised and mild.