Incidence of Co-Infections of HIV, Herpes Simplex Virus Type 2 and Syphilis in a Large Cohort of Men Who Have Sex with Men in Beijing, China

The HIV-epidemic among MSM in China has worsened. In this key population, prevalence of HSV-2 and syphilis infection and co-infection with HIV is high. A longitudinal study was conducted (n = 962) in Beijing, China, with three overlapping cohorts (n = 857, 757 and 760) consisting of MSM that were free from pairs of infections of concern (i.e. HIV-HSV-2, HIV-syphilis, HSV-2-syphilis) at baseline to estimate incidence of HIV, HSV-2, syphilis, and those of co-infection. The incidence of HIV, HSV-2 and syphilis in the overall cohort was 3.90 (95% CI = 2.37, 5.43), 7.87 (95% CI = 5.74, 10.00) and 6.06 (95% CI = 4.18, 7.94) cases per 100 person-years (PYs), respectively. The incidence of HIV-HSV-2, HIV-Syphilis and HSV-2-Syphilis co-infections was 0.30 (95% CI = 0.29, 0.88), 1.02 (95% CI = 0.13, 2.17) and 1.41 (95% CI: 0.04, 2.78) cases per 100 PYs, respectively, in the three sub-cohorts constructed for this study. The incidence of HIV, HSV-2 and syphilis was very high and those of their co-infections were relatively high. Such co-infections have negative impacts on the HIV/STI epidemics. Prevention practices need to take such co-infections into account.