Safety profile of the COVID-19 vaccine in chronic vs. non-chronic populations: evidence from a retrospective cohort study.

Abstract

This retrospective cohort study evaluated the safety profile of COVID-19 vaccination after the administration of three doses among 1,000 participants in Kosovo, including 600 individuals with chronic diseases and 400 without chronic conditions. Data were collected from medical records and standardized questionnaires on post-vaccination adverse events. Overall, 68.5% of participants reported at least one adverse effect, with a higher incidence among those with chronic diseases (74.3%) compared with non-chronic individuals (59.7%, p = 0.01). The most common reactions were mild and transient, including local injection site pain (39.2%), fatigue (27.6%), headache (21.4%), and mild fever (18.9%), while severe effects such as allergic or cardiac reactions were rare (1.2%). No significant differences were found among vaccine types. The findings indicate that COVID-19 vaccines were generally safe and well tolerated in both chronic and non-chronic populations, emphasizing the importance of continued pharmacovigilance and public health efforts to maintain vaccine confidence.