The Canadian National Vaccine Safety (CANVAS) network: Cross-sectional analysis of seasonal influenza vaccine safety in children during the 2013/2014 to 2019/2020 influenza seasons

The Canadian National Vaccine Safety (CANVAS) network is a participant-centered, active surveillance system that assesses vaccine safety across Canada. Our study examined the safety profile of influenza vaccines administered to children during seven consecutive influenza seasons, from 2013/2014 to 2019/2020, to establish a baseline for health events in vaccinated and unvaccinated children before the COVID-19 pandemic. Data were collected using an online survey after a 7-day period for vaccinated and unvaccinated participants. Descriptive and inferential analyses explored the association between the influenza vaccine and health events, including associated symptoms. The proportion of health events were comparable in vaccinated and unvaccinated children. Adjusted regression models identified no statistical difference in the occurrence of health events assessed. The most frequently reported symptoms were fever, gastrointestinal symptoms (i.e., nausea/vomiting/diarrhea), and cough. Our findings observed low incidence of health events in both vaccinated and unvaccinated groups in this multi-year study.