The role of syphilis self-testing as an additional syphilis testing approach in key populations: a systematic review and meta-analysis.

BACKGROUND: Syphilis is causing epidemics in many countries. Syphilis self-testing (SST) has potential to increase testing and treatment coverage in the same manner as documented for self-testing of, for example, HIV, hepatitis C virus, and COVID-19. We aimed to synthesise current evidence on the utility of SST. METHODS: We conducted a systematic review and, where possible, meta-analysis. We searched MEDLINE, Embase, CINAHL, Scopus, and Web of Science for publications published from Jan 1, 2000, to Oct 13, 2022. We included publications with original data on any syphilis rapid tests, including dual HIV-syphilis tests. Study populations were not restricted. We used random-effects meta-analysis to calculate the pooled proportion of people offered SST who undertook the test. The systematic review was registered in PROSPERO (CRD42022302129). FINDINGS: In total, 40 499 citations were identified. 11 publications from seven studies from the USA, Zimbabwe, and China met eligibility criteria. Of those, four studies reported data from men who have sex with men and five studies used dual HIV-SST. Using data from one randomised controlled trial and three observational studies, the pooled proportion of people who received SST kits who undertook the test was 88% (95% CI 85-91). No studies provided data on the sensitivity or specificity of SST. Overall, user and provider preference for SST was high, with participants reporting convenience, privacy, rapid results, autonomy, trust in blood-based tests, decreased facility contact, and time savings, with individuals being able to correctly self-test. Publications from China reported that SST had lower costs per person tested than existing facility-based testing options. INTERPRETATION: Our review builds on the literature for self-testing across different disease areas and demonstrates that SST has the potential to reach underserved populations. As this review found that SST use was acceptable and feasible to implement, SST can be used as an additional syphilis testing approach. Since no data on the sensitivity and specificity of SST were found, further implementation research will be required to guide the best strategies for SST service delivery and future scale-up. FUNDING: WHO, Australian National Health and Medical Research Council, and Unitaid.