Conclusion
gonorrhea, gonorrhea disease, chlamydia
RECRUITMENT, GONORRHEA, SENSITIVITY
Innovative and effective intervention strategies are urgently needed to fill the gap between the high global burden of chlamydia and gonorrhea disease and suboptimal STI testing services. A pay-it-forward approach has the potential to enhance chlamydia and gonorrhea testing uptake among Chinese FSWs. It may be a valuable tool for scaling up STI services. Further implementation research is needed to inform the transition of pay-it-forward research into practice.We are grateful to all participants in this study, without whom this study could not have been completed. We thank the study implementation team at the Dermatology Hospital Guangzhou site for all their dedication and efforts, which made this research possible. We appreciate the collaborating chronic-disease control centers in Maoming, Yunfu, Yangjiang, and Yingde for their help in facilitating and coordinating this study. Funding for this study came from the National Natural Science Foundation of China (grant 81903371) and the National Institutes of Health (grants NIAID K24AI143471 and R34MH119963).Authors' Contributions: WT and CW conceived the study. YX and MX led the piloting and implementation of the study. MX, CW, and BY assisted with recruitment. YX cleaned and analyzed the data and generated figures and tables to present the paper’s findings. JJO advised on modeling approaches. WT, YX, and CW wrote the initial draft of the paper. DW, JJO, TEW, and JDT provided constructive comments and edited the manuscript. All authors read and authorized the final version.Conflicts of Interest: None declared.CONSORT 2010 checklist.Sensitivity analysis of number of cluster size.Cost effectiveness analysis.The reason for a test or not in the PIF program and the program's perceived benefits.