Buenos Aires Cohort of Men who have sex with Men: Recruitment, retention and seroincidence of HIV and other sexually-transmitted infections.

SEGURA M; SOSA ESTANI S; MARONE R; PANDO MA; REY J; DURANTI R; SANCHEZ J; WEISSENBACHER M; AVILA MM

Rio de Janeiro

Conferencia; The 3rd IAS Conference on HIV Pathogenesis and Treatment.; 2005

IAS

Introduction: In Argentina men who have sex with men (MSM) represent 20.5% of the total number of AIDS cases reported. Previous baseline studies conducted in the years 2001-02 yielded an HIV prevalence of 13.8 % and an annual incidence rate of 6.0 % person-year in the capital city of Buenos Aires.   Objectives: To establish an MSM cohort to evaluate the feasibility of recruitment and retention, and to determine incidence of HIV, hepatitis C (HCV), and syphilis for one year.   Methods: HIV-negative volunteers were invited to participate in a closed cohort study. Inclusion criteria: 1) 18 to 60 years of age; 2) sexual intercourse with other men; 3) not having injected drugs, and 4) providing informed consent and commitment for follow-up after 6 and 12 months. Blood samples were screened at each of 3 visits for HIV and HCV (by ELISA), and T. pallidum (by VDRL). Pre and post-test counseling was provided.   Results: During the period of February-December 2003, a total of 811 HIV-negative MSM were screened; 327 agreed to participate in the follow-up study. Mean age was 31.6 ± 8.7 year. The 6 and 12-month visit retention were 97.2% and 91.5%, respectively. After one year 12 MSM seroconverted for HIV infection, an incidence of 3.9 % person-year (95% CI = 2.0-6.7).Nine volunteers seroconverted for VDRL incidence 3.0% person-year (95% CI = 2.8-3.2) and no one seroconverted for HCV.   Conclusions: Successful recruitment and high levels of retention were attained in an MSM cohort in Buenos Aires. There was a drop in the annual HIV  incidence  rate from 6.0 % in 2001-2002 to 3.9 % in 2004 but this difference was not stadistically significant (p=0.21). It is crucial to develop specific prevention strategies. Given both the high incidence and retention rates noted, future HIV vaccine trials should be considered in this high-risk group.