Monitoring for HIV-1 infection and other sexually-transmitted infections (STIs) in a cohort of men who have sex with men (MSM) in Buenos Aires, Argentina.

AVILA MM; MARONE R; PANDO MA; SEGURA M; DURANTI R; SANCHEZ J; WEISSENBACHER M

Bangkok

Conferencia; XV International AIDS Conference; 2004

IAS

Introduction: In Argentina, MSM represented at least 20% of the total number of notified AIDS cases in 2002. Recent baseline studies performed in our laboratory together with a non-governmental organization estimated an HIV prevalence of 13.8% and an annual incidence rate of 6.0% in Buenos Aires.  Objectives: To recruit and retain a cohort of MSM and to determine the annual incidence and risk factors associated with HIV-1 and T. pallidum infections. To analyze the behavioral factors related to retention of volunteers and evaluate the possibility of including this population in future vaccine trials. Methods: Men between the ages of 18 to 60 years, and who reported having had sexual relations with other men in the past 6 months, were screened for HIV-1 and syphilis.  Those who were found to be HIV-negative, did not report injecting drug use, accepted to provide appropriate written informed consent, and who agreed to be informed of their HIV serology and follow-up counseling, were included. Initial entry and 6 month blood samples were collected for screening for HIV-1, HBV, HCV and VDRL reactivity. Sociodemographic and epidemiologic data were also obtained every 6 months. Results: A total of 897 MSM were studied from February to December 2003. Past infection with HIV-1 was detected in 77 (8.6%), HBV in 202 (22.5%), HCV in 4 (0.4%), and VDRL reactivity in 62 (6.9%). All subjects found to be HBV-negative were offered HBV vaccination. Out of the 820 HIV-1 negative at baseline, 333 were selected to participate in the follow-up study, after a physical and psychological evaluation. Up until mid-January 2004, 194 volunteers have returned for the 6-month visit (92.0 % retention rate at 6 month) and 6 have been shown to seroconvert showing an Incidence Density of 6.2% person/year (95% CI 2.5-13.5). Conclusions: A cohort of 333 MSM was recruited in Buenos Aires. The initial estimates of HIV-1 incidence reveal that this may be a convenient group in which to deploy intervention studies, such as HIV vaccines, in the future.