Optimizing Peer Distribution of Syphilis Self-Testing Among Men Who Have Sex with Men in China: A Multi-City Pragmatic Randomized Controlled Trial

Syphilis testing uptake is low among men who have sex with men (MSM) around the world. Syphilis self-testing (SST) may complement facility-based testing; the distribution model is yet to be explored. This study aimed to investigate the effectiveness of peer distribution of syphilis self-testing on promoting syphilis testing. We conducted a three-arm, unblinded, parallel individually randomized controlled trial among MSM in three cities in Guangdong, China. Inclusion criteria were: men who were born biologically male, aged 18 or above, have ever had sex with a man, will refer the interventions to peers, and will take the three-month follow-up survey. Enrolled indexes were randomly assigned in a 1:1:1 ratio into standard-of-care arm (SOC arm), standard SST delivery arm (S-SST arm), and a web-based referral link SST delivery arm (RL-SST arm). The primary outcome was the number of returned photograph-verified syphilis testing results per index. A total number of 300 indexes were enrolled, with 100 indexes in each arm. The number of verified syphilis tests per index conducted by alters was 0.05 in the control arm, 0.51 in the S-SST arm, and 0.31 in the RL-SST arm. The cost per alter tested was $760.60 for SOC, $83.78 for S-SST, and $93.10 for RL-SST. Minimal adverse event was reported among both indexes and alters during the study. This study showed that peer distribution of SST could improve syphilis testing uptake among MSM in China compared to facility-based testing. This approach warrants further consideration as part of expanding syphilis self-testing.