HIV seroincidence estimates among vulnerable populations in Buenos Aires using a serologic testing algorithm for recent HIV seroconversion.

VIGNOLES M; AVILA MM; MARTINEZ PERALTA L; PANDO MA; SHEPPARD H; MAULEN S; RADULICH G; ROSSI D; BENETUCCI J; WEISSENBACHER M

Rio de Janeiro

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

IAS

Background:  The aim of this study was to estimate the incidence of HIV-1 infection in populations with different routes of transmission where few or no incidence studies have been carried out, using the STARHS. Methods: Serum samples from 6 HIV seroprevalence surveys conducted Buenos Aires were used. These were: men who have sex with men (MSM), injecting drug users (IDU), asymptomatic women consulting for an HIV infection (AW), heterosexual individuals consulting about a new sexually transmitted infection (STI), individuals with tuberculosis (TB), and non-injecting cocaine users (NICU). HIV-1 seropositive samples were tested with the modified Vironostika HIV-1 Microelisa System. Using a window period of 170 days and cut-off: 1.0 annual incidence estimates were calculated with STARHS. Results:  Population MSM IDU AW            AW              AW STI NICU TB Year 2000-2001 2000-2001 1998 1999 2000 2001-2002 2002-2003 2001-2002 Sample # 694 174 716 660 566 801 504 211 HIV-positive 96 77 71 80 93 58 32 35 Adjusted annual HIV seroincidence (per 100 person-years) 6,7 0,0 0,4 4,6 10,2 2,0 3,1 2,4 (95% CI) (3,7-9,7) - (0,0-1,1) (2,1-7,1) (6,0-14,3) (0,5-3,5) (0,8-5,5) (0,0-5,8) HIV seroprevalence (%) 13,8 44,3 9,9 12,1 16,4 7,2 6,3 16,6 (95% CI) (11,4-16,7) (36,8-52,0) (7,9-12,4) (9,8-14,9) (13,5-19,8) (5,6-9,3) (4,4-8,9) (12,0-22,4) Conclusions: The high HIV incidence found in some vulnerable populations from Buenos Aires indicate the urgent need for planning specific prevention strategies for them, mainly for MSM, NICUs and AW. STARHS-estimated incidence among MSM was confirmed with a longitudinal cohort study during the same period of time [Incidence: 6.0%person/year (3.1-11.0)]. Some of the groups with high HIV incidence may be considered suitable for volunteer participation in HIV vaccine clinical trials.