Efficacy of the Outsmart HPV Intervention: A Randomized Controlled Trial to Increase HPV Vaccination among Young Gay, Bisexual, and Other Men Who Have Sex with Men

Background: Routine human papillomavirus (HPV) vaccination is recommended for young adults, yet many young gay, bisexual, and other men who have sex with men (YGBMSM) remain unvaccinated. We report the efficacy of Outsmart HPV, a web -based HPV vaccination intervention for YGBMSM. Methods: From 2019 to 2021, we recruited YGBMSM in the United States who were ages 18-25 and unvaccinated against HPV (n = 1,227). Participants were randomized to receive either: (i) Outsmart HPV content online and monthly interactive text reminders (interactive group); (ii) Outsmart HPV content online and monthly unidirectional text reminders (unidirectional group); or (iii) standard information online about HPV vaccine (control group). Regression models compared study groups on HPV vacci-nation outcomes. Results: Overall, 33% of participants reported initiating the HPV vaccine series and 7% reported series completion. Initia- tion was more common among participants in the interactive group compared with the control group [odds ratio (OR) = 1.47, 98.3% confidence interval (CI): 1.03-2.11]. Completion was more common among participants in both the interactive group (OR = 3.70, 98.3% CI: 1.75-7. 83) and unidirectional group (OR = 2.26, 98.3% CI: 1.02-5.00) compared with the control group. Participants who received Outsmart HPV content reported higher levels of satisfaction with online content com-pared with the control group. Conclusions: Outsmart HPV is an efficacious and acceptable HPV vaccination intervention for YGBMSM. Future efforts are needed to determine how to optimize the intervention and dissem-inate it to settings that provide services to YGBMSM. Impact: Outsmart HPV is a promising tool for increasing HPV vaccination among YGBMSM with the potential for wide dissemination.