Preventing Postvaccination Presyncope and Syncope in Adolescents: A Randomized Controlled Trial of a Clinic-Based Intervention

OBJECTIVE: To study the impact of a combined intervention using Buzzy plus simultaneous distraction (playing video games on a tablet) on the incidence of postvaccination presyncope and syncope. STUDY DESIGN: We performed a randomized-controlled trial of a combined intervention designed to reduce presyncope, which is more common than syncope, and has served as a surrogate for syncope in previous studies. Adolescents 10-14 years-old receiving ≥1 intramuscular vaccine were randomized 1:1 to a combined intervention group including Buzzy (vibration/cool pack device to reduce injection site pain) and a video game (distraction) or a standard of care control group. The primary outcome was the efficacy of the combined intervention to decrease presyncope. Secondary outcomes included changes in prevaccination and postvaccination state anxiety; postvaccination pain; and participant acceptability of the intervention. RESULTS: We enrolled 332 adolescents and included all in the modified intention to treat group. Presyncope was lower in the intervention group (36%) compared with the control group (48%, P = .02). Pain at 1-3 minutes was also decreased in the intervention group compared with the standard of care group with mean postvaccine Wong-Baker Faces Pain Scores of 3.3 vs 2.5 (P = .006), respectively. CONCLUSIONS: We identified an acceptable clinic-based intervention that reduces presyncope in young adolescents receiving routine vaccines. This efficacy was likely driven by decreases in postvaccination pain. TRIAL REGISTRATION: https://clinicaltrials.gov/study/NCT04772755.