Monitoraggio della sicurezza dei vaccini COVID-19 in popolazioni speciali attraverso sistemi di farmacovigilanza attiva: risultati del progetto europeo Covid-Vaccine-Monitor

The COVID-19 pandemic posed an unprecedented global health challenge, accelerating the processes of vaccine development, authorization, and distribution. In this rapidly evolving context, ensuring timely, accurate, and transparent monitoring of vaccine safety became a critical public health priority. Traditional pharmacovigilance systems, mainly based on spontaneous reporting of suspected adverse reactions, remain essential for signal detection but are limited by underreporting and incomplete incidence data. To address these limitations, complementary active pharmacovigilance approaches have been developed to provide more comprehensive and comparative information on post-vaccination adverse events in defined populations. Within this framework, the European “Covid Vaccine Monitor” (CVM) project, funded by the European Medicines Agency (EMA), implemented a large-scale cohort monitoring system to assess the safety of COVID-19 vaccines across Europe. The study collected patient-reported safety data through standardized web applications—Lareb Intensive Monitoring (LIM) and ResearchOnline (RO)—in 11 European countries (Belgium, France, Italy, Ireland, the Netherlands, Portugal, the United Kingdom, Romania, Slovakia, Spain, and Switzerland) between February 2021 and February 2023. Participants enrolled within 48 hours after receiving the first or booster dose and completed a baseline questionnaire followed by periodic follow-ups to report local, systemic, serious, or special-interest adverse drug reactions (ADRs). Special populations—including immunocompromised individuals, allergic subjects, those with prior SARS-CoV-2 infection, pregnant or breastfeeding women, and minors aged 5–17—were analyzed alongside matched control groups through propensity score matching. Data harmonization was achieved via a Common Data Model (CDM), and analyses were performed centrally using descriptive and inferential statistics. The results demonstrated the feasibility and value of active pharmacovigilance systems for monitoring vaccine safety in both general and special populations. The integration of harmonized, patient-reported data at the European level strengthened post-marketing surveillance and enabled timely and comparative safety assessments. The methodological insights gained from the CVM project provide a foundation for the development of proactive and sustainable vaccine safety monitoring networks beyond the COVID-19 pandemic.