Feasibility and acceptability of pay-it-forward in increasing uptake of HPV vaccination among 15-18-year-old girls in China: Pilot RCT Results.

China has low human papillomavirus (HPV) vaccination rate due to limited public funding and mistrust in domestic vaccines. This pilot study aimed to evaluate the feasibility, acceptability, and preliminary effectiveness of an innovative pay-it-forward strategy to improve HPV vaccine uptake among adolescent girls. Conducted at a community health center in Western China (Jan 4 - Feb 18, 2022), the study recruited 100 adolescent girls (ages 15-18) with no prior HPV vaccination. Participants were randomly assigned to either the standard-of-care arm (self-paid vaccines, n=50) or the pay-it-forward arm (subsidized vaccines, hand-written postcards, and the opportunity to donate and/or write postcards, n=50). Feasibility was assessed through recruitment, retention, and questionnaire completion rates. Acceptability and feasibility were measured using the standard scale. Preliminary effectiveness was evaluated by first-dose vaccination rate. Of 109 screened participants, 100 were eligible to participate (91.7%). Retention rate was 100% in both arms. Questionnaire completion rate was 98% (49/50) in the pay-it-forward arm and 82% (41/50) in the standard-of-care arm. Most participants self-reported that the strategy was feasible (97.6%, 41/42) and acceptable (90.5%, 38/42). Ninety seven percent (97/100) of participants made vaccination appointments. The first-dose HPV vaccine uptake rate was 98% (49/50) in the pay-it-forward arm and 82% (41/50) in the standard-of-care arm (P<0.05). No serious adverse events were identified. The pay-it-forward strategy was feasibility, acceptability, and showed preliminary effectiveness in increasing HPV vaccination uptake. Further refinement and population-based recruitment are needed to better reflect local contexts and enhance the generalizability of the formal trial.