Low Level of Accurate Knowledge of Undetectable Equals Untransmittable (U = U) Among Men Who Have Sex with Men (MSM) Challenges U = U Achievement in Chengdu, Southwestern China

The introduction of the undetectable equals untransmittable (U = U) statement significantly reduces HIV stigma and provides an empirical basis for achieving “zero transmission.” U = U messaging has gained increasing support and is well-developed in several countries. However, the current status of accurate knowledge of U = U and its associated factors among men who have sex with men (MSM) in China remians unclear. We conducted a cross-sectional survey among MSM recruited in Chengdu, China, from March to May 2022 to investigate the percentage of those who knew U = U accurately and to explore associations between sexual risk behaviors, HIV testing, socio-behavioral measures, and accurate knowledge of U = U. Of 497 MSM included in our study, 23.4% (116/497) had accurate knowledge of U = U. More than half of the participants (63.2%, 314/497) reported multiple sexual partnerships, 15.7% (78/497) used substance during sex, 37.4% (186/497) reported inconsistent condom use, and 76.1% (378/497) took HIV testing in the past six months. Factors associated with accurate knowledge of U = U among MSM included substance use during sex (multivariate odds ratios ORm = 1.96; 95%CI: 1.13–3.41), HIV status tested in the last six months (ORm = 2.07; 95%CI: 1.14–3.77), HIV-related literacy (ORm = 1.41; 95%CI: 1.14–1.74) and perceived higher risk of HIV infection (ORm = 1.11; 95%CI: 1.02–1.21). The findings indicate that great challenges need to be conquered for U = U achievement among the MSM population in Chengdu, China. Intervention strategies should be prioritized in health education on high-risk behaviors such as group sex and substance use, information provision and counseling of U = U in HIV testing services, and encouraging U = U knowledge sharing among MSM with their partners in China.