Drive-thru influenza immunization: Fifteen years of experience

Background: In 1995, a yearly drive-thru immunization program was initiated in Louisville, KY. Since then, more than 50,000 doses of influenza vaccine have been administered, with no reports of syncopal episodes or vehicular accidents. This report aimed to identify reported adverse events from other areas that could threaten drive-thru mass immunization approaches.Methods: To identify reported adverse events in any drive-thru mass immunization event, the authors queried the following sources: 1) the vaccine adverse event reporting system, 2) court cases, 3) healthcare risk management databases, 4) MEDLINE, and 5) communication with vaccine experts. The authors also calculated the probability of syncopal episodes using data from our past immunization experiences to further elucidate the possibility of these events occurring.Results: No adverse events due to a drive-thru mass immunization event were identified in any of the sources queried. In our data, the forecasted probability of one adverse event was 0.8 percent for a 2-day event (20,000 immunizations).Conclusions: Although syncope may occur following immunization, it is a risk that can be managed, and due to the rarity of these events, should not be used as a reason to avoid drive-thru administration of influenza vaccine.