Objective: To gain insight in the ongoing HIV transmission, we compared sexual risk behaviour pre-HIV and post-HIV seroconversion in 206 MSM participating in the Amsterdam Cohort Studies (1984-2008) before and after the introduction of combination antiretroviral therapy (cART).
Design and methods: MSM completed behavioural questionnaires and were tested for HIV antibodies every 6 months. Trends in anal intercourse and number of sex partners from 4 years before HIV seroconversion until 4 years after diagnosis were analysed with latent class random effects logistic regression models.
Results: The risk of having unprotected anal intercourse (UAI) 1 year after HIV diagnosis decreased significantly when compared with 1 year before diagnosis in both the pre-cART era [difference, 30%; 95% confidence interval (CI), 22-36%] and cART era (difference, 19%; 95% CI, 9-30%). In contrast to a continuing decrease of UAI in the pre-cART era, the probability of UAI in the cART era increased again to preseroconversion levels (61%; 95% CI, 48-74%)) 4 years after diagnosis.
Conclusion: This study provides evidence that recently seroconverted MSM reduce their sexual risk behaviour following HIV diagnosis both in the pre-cART as well as the cART period. However, in the cART period this reduction in sexual risk behaviour is less and returns to pre-cART levels within 4 years. These findings not only confirm the need for early HIV testing but also make it clear that much more effort should go into identifying, counselling, and possibly treating recently seroconverted MSM who have been found to be one of the most important drivers of HIV transmission among MSM.