Risks of an adverse event following influenza vaccination are far less common than complications related to influenza itself, and the adverse events are generally localised and mild.
Injected trivalent inactivated influenza vaccines are most commonly used throughout the world. Influenza antigen preparation varies between manufacturers.
This protocol describes the common methodology to be applied to established health data registries across seven participating EU/EEA Member States to estimate vaccine effectiveness for Coronavirus disease 2019 (COVID-19) in children and adolescents aged 5-17 years old.