Pay-it-forward enhanced uptake of Mycoplasma pneumoniae testing among pediatric outpatients in China: a pragmatic cluster randomized controlled trial

Pay-it-forward intervention involve a person receiving a free test and then having the option to donate money to support testing for others. This study assessed the effectiveness of a pay-it-forward in increasing Mycoplasma pneumoniae ( M. pneumoniae ) testing uptake among children in Wuxi, China. We conducted a two-arm, pragmatic superiority cluster randomized controlled trial (Clinical Trial registration: ChiCTR 2300078623). Participants were children under 14 years old attending two outpatient pediatric clinics, randomized into pay-it-forward or standard-of-care arms. In the pay-it-forward arm, participants received free M. pneumoniae testing and could voluntarily contribute to future participants' testing costs. The standard-of-care arm participant needed to pay 14 USD for tests. The primary outcome was M. pneumoniae testing uptake based on administrative records. Between December 2 and December 20, 2023, 320 children were enrolled (160 per arm). M. pneumoniae testing uptake was significantly higher in the pay-it-forward arm (72.5%) than in the standard-of-care arm (34.4%) (adjusted proportion difference 39.6%, 95% confidence interval 23.6–55.7%). In the pay-it-forward arm, 9.5% of participants donated money. The intervention effect showed variation in caregivers’ education level and study sites. No adverse events were reported. The pay-it-forward intervention significantly increased M. pneumoniae testing uptake among symptomatic children, demonstrating the feasibility of innovative diagnostic incentives for respiratory pathogens.