Decrease in the proportion of HIV-positive MSM followed up in hospital likely to transmit HIV between 2003 and 2011 in France: results from national representative surveys (ANRS VESPA-1 and VESPA-2)

Background: In France, men who have sex with men (MSM) still remain the population most at risk of HIV infection, with no decrease in HIV incidence being observed. We aimed to assess changes in sexual behavior among HIV-positive MSM attending outpatient clinics using data from two national representative surveys, conducted in 2003 and 2011, respectively, by considering indicators reflecting the diverse factors that might impact HIV sexual transmission in this population.
Methods: ANRS VESPA-1 and -2 were cross-sectional surveys conducted among adult PLWH attending French hospitals. Socio-behavioural and medical data were collected. The present analysis included men who self-reported they were gay, bisexual or had had at least one male partner in the previous year (n=1117 VESPA-1, n=1337 VESPA-2). HIV-negative or unknown status partners were considered serodiscordant. The outcome was inconsistent condom use for oral or anal sex with a serodiscordant steady partner in the previous 12 months, or with a serodiscordant casual partner during their last sexual encounter. Chi2 tests were performed on weighted and calibrated data.
Results: Compared with MSM included in 2003, those in 2011 were significantly (p< 10-3) older, were diagnosed with HIV longer, and reported less sexual activity. However, they had better immunovirological status (CD4>500 cells/mm3 and undetectable viral load (VL)). Globally, between 2003 and 2011, the proportion of MSM reporting inconsistent condom use with a serodiscordant steady (79% vs 86% for oral sex; 23% vs 25% for anal sex, respectively) or casual partner (76% vs 80% for oral sex; 23% vs 18% for anal sex, respectively) did not differ significantly. However, the proportion of MSM with a detectable VL engaging in unprotected intercourse with serodiscordant main (23% vs 9% for oral sex; 7% vs 1% for anal sex, respectively) and casual partners (28% vs 7% for oral sex; 8% vs 4% for anal sex, respectively) decreased noticeably.
Conclusions: The proportion of HIV-positive MSM likely to transmit HIV decreased between 2003 and 2011 despite no increase in condom use. To have an impact on HIV epidemic, acting on behavioral changes will not be enough without achieving an undetectable viral load in all treated seropositive people.

M. Suzan-Monti1,2,3, B. Demoulin1,2,3, R. Dray-Spira4,5, F. Lert6, B. Spire1,2,3, ANRS-VESPA2 Study Group
1INSERM, UMR 912 (SESSTIM), Marseille, France, 2Aix Marseille Université, UMR_S 912, IRD, Marseille, France, 3ORS PACA, Observatoire Régional de la Santé Provence-Alpes-Côte d'Azur, Marseille, France, 4INSERM, UMR_S 1136, Pierre Louis Institute of Epidemiology and Public Health, Team Research in Social Epidemiology, Paris, France, 5Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1136, Pierre Louis Institute of Epidemiology and Public Health, Team Research in Social Epidemiology, Paris, France, 6Centre de Recherche en Épidémiologie et Santé des Populations, Inserm U 1018, Villejuif, France