Shanshan Zhao
Conducting observational post-marketing vaccine and drug safety surveillance is important for detecting rare adverse events (AEs) not identified pre-licensure. Highly frequent monitoring of vaccine safety has been proposed using continuous sequential monitoring methods, but such frequent testing may result in a loss of power. Interim monitoring using group sequential methods has been widely used to monitor safety in clinical trials, but the performance has not been examined in observational settings or when more frequent surveillance is desired. We conducted a simulation study to compare the power and timeliness to correct detection of an elevated AE risk among vaccinated people. We vary both the testing frequency (daily, weekly, monthly, quarterly) and shape of the stopping boundary (Pocock, O’Brien-Fleming). Results of this evaluation can inform the design of future sequential monitored safety studies.
