Recent acquired STD and the use of HAART in the Italian Cohort of Naive for Antiretrovirals (I.Co.N.A): Analysis of the incidence of newly acquired hepatitis B infection and syphilis

Objective: To estimate the incidence of newly acquired syphilis (n-syphilis) and hepatitis B infection (n-hepatitis B) in I.Co.N.A. and to evaluate the impact of HAART, calendar date and risk group. Methods: Cohort study: Incidence was calculated by person-years analyses. Poisson regression was used for the multivariate model. Results: The rate of n-syphilis was 23.4/1,000 PYFU and it increased over time; HIV transmission risk was the most important predictor: men who have sex with men (MSM) had a considerable higher risk (RR 5.92, 95% CI 2.95-12.13 vs IDU/exIDU, p <0.0001). The rate of n-hepatitis B was 12.2/1,000 PYFU; it declined in recent years and halved per 10 years age. Patients with HIV-RNA <500 copies/ml had a 60% reduced risk of n-hepatitis B if they were treated with HAART compared with not treated individuals. Conclusions: In our population, the use of HAART was not associated with a higher risk of newly acquired sexually transmitted diseases (STD). Suppressive HAART was associated with a lower risk of HbsAg seroconversion. Incidence of n-hepatitis B has recently been declining possibly due to herd immunity provided by vaccination policies. The risk of acquiring n-syphilis has increased over time and it is higher in the population of MSM compared with other categories of HIV exposure.