Safety data collection
Participants were observed by a study nurse or pediatrician for at least
15 minutes after vaccination. Participants reported prespecified adverse
reactions (ARs) in an online or paper-based diary for 7 days after
vaccination. Unsolicited adverse events (AEs) were captured for up to 28
days after vaccination. Severe AEs, involving hospitalizations,
life-threatening complications, disabilities, deaths and birth defects
of their offspring, or breakthrough COVID-19, would be monitored for 3
years after vaccination. Adverse events reported were reviewed by
investigators, who determined any possibility of causal relationship
with the study vaccine.