Syphilis epidemic among men who have sex with men: A global systematic review and meta-analysis of prevalence, incidence, and associated factors

BACKGROUND: We aimed to estimate the prevalence and incidence of syphilis at global, regional and national levels for human immunodeficiency virus (HIV)-positive and HIV-negative men who have sex with men (MSM) and explore the association between demographic and social behavioural factors and syphilis infection. METHODS: We searched PubMed, Embase, and the Cochrane Library from 1 January 2012 to 31 December 2022 for studies of reported crude syphilis prevalence or incidence in MSM or with sufficient data to calculate prevalence or incidence rate in MSM. RESULTS: We included 376 articles reporting on 409 records from 62 countries to calculate syphilis prevalence and incidence in MSM. The pooled prevalence of syphilis in MSM was 10.4%, with substantial differences between countries and regions. Syphilis prevalence was substantially higher in HIV-positive than in HIV-negative MSM. The pooled incidence of syphilis in MSM was 76.4 per 1000 person-years. Older age, lower education, nitrite or recreational drug use, group sex, and multiple sexual partners were identified as risk factors for syphilis infection. CONCLUSIONS: A disproportionate geographic pattern of syphilis infection in MSM and significant threats of syphilis infection were revealed. The ‘hidden risk’ in specific regions and the inadequately elucidated drivers of high-risk behaviours, need to be fully acknowledged and addressed.

• Epidemiology and Determinants of Health
  • Epidemiology
• Population(s)
  • Men who have sex with men
  • General HIV+ population
  • General HIV- population
• Co-infections
  • Syphilis