Repeated syphilis episodes in HIV-infected men who have sex with men: a multicentre prospective cohort study on risk factors and the potential role of syphilis immunity. Open Forum Infectious Diseases
Roth et al. aimed to identify risk factors for incident syphilis and in particular for repeated syphilis episodes among men who have sex with men (MSM) from the Swiss HIV Cohort Study (SHCS).
Within a 14-year observation period, the authors included 2’513 HIV-infected MSM with an initially negative syphilis test. In the univariable and multivariable analysis, the number of prior syphilis episodes (adjusted hazard ratio [aHR] per 1-episode increase, 1.15; 95% confidence interval [CI], 1.01–1.31), having occasional sexual partners with or without condomless anal sex (aHR, 4.99; 95% CI, 4.08–6.11; and aHR, 2.54; 95% CI, 2.10–3.07), and being currently on antiretroviral therapy (aHR, 1.62; 95% CI, 1.21–2.16) were associated with incident syphilis.
In conclusion, in HIV-infected MSM, there was no indication of a decreased syphilis risk with repeated syphilis episodes. The extent of sexual risk behavior over time was the strongest risk factor for recurrent syphilis episodes. The observed association of ART with repeated syphilis episodes may not be causal and warrants further epidemiological and immunological investigation.