Lessons learned from COVID-19, H1N1, and routine vaccine pharmacovigilance in the United States: a path to a more robust vaccine safety program

Vaccine pharmacovigilance is an essential component of vaccine safety programs. Vaccine pharmacovigilance refers to detecting uncommon adverse events following immunization (AEFI), determining whether they are due to the vaccine or are only a coincidence, and, for those AEFI considered related to vaccination, characterizing them further. When AEFI are due to vaccination, it is important to characterize the attributable risk and ascertain the biological mechanism causing the adverse reaction to inform efforts to prevent or mitigate the risk. A robust post-authorization safety system is necessary for vaccine decision-making, clinical recommendations, vaccine compensation, and vaccine communication and confidence.