961 
HIV Incidence and Syphilis Rates among Men Who Have Sex with Men at High Risk for HIV-1 Infection in 5 Andean Cities
Juan Guanira*1, J Lama1, P Goicochea1, P Segura1, O Montoya2, S Montano3, T Kochel3, R Grant4, and J Sanchez1
1Civil Assn Hits Hlth and Ed, Lima, Peru; 2Fndn Ecuatoriana Equidad, Quito, Ecuador; 3US Naval Med Res Ctr Detachment, Lima, Peru; and 4Gladstone Inst of Virology and Immunology, Univ of California, San Francisco, US
Background: In
the HAART era, epidemiological surveillance is complicated by prolonged
survival, which will increase prevalence even if incidence decreases. More
direct indicators of incidence, drug resistance, and community viral load are
needed to track the epidemic in the current era, and to identify sites suitable
for prevention trials.
Methods: To estimate HIV incidence and syphilis rates, at
the beginning of 2006, we conducted a cross-sectional survey among high risk men
who have sex with men (MSM) in 4 Peruvian cities and in Guayaquil, Ecuador.
Accrual was expected to be 4 months in order to enroll 570 men in each city. Men
who referred not knowing their HIV serostatus or not having had an HIV test
during the previous 12 months were contacted at previously identified MSM
venues and referred to study clinics. Study outreach promoted the
self-exclusion of HIV+ men. HIV-1 or -2 antibodies were screened by Determine
HIV-1/2 Rapid Test and confirmed by Western blot. Early HIV infection and
incidences were estimated by the BED EIA according to the manufacturer’s
instructions. Rates of syphilis (RPR ≥1:1 and MHA-TP+) and
early syphilis (RPR ≥1:16 and MHA-TP+) were computed.
Results: A total of 2608 MSM were enrolled. Accrual by
city was as follows: Guayaquil 538 (94.4%), Arequipa 418 (73.3%), Sullana 562 (98.6%), Ica 414 (72.6%), and Lima
676 (118.2%). Estimated HIV incidence was 7.4% (95%CI 3.5 to 11.9) in Guayaquil;
3.1% (95%CI 1.0 to 5.3) in Lima; 2.4% (95%CI 0.0 to 4.8) in Ica; and 1.4 (95%CI
0.0 to 3.0) in Sullana. No incident cases were found in Arequipa. The highest syphilis rates were
observed in Guayaquil (27.5%) and Ica (18.1%), and early syphilis rates in Guayaquil
(11.5%) and Lima
(7.3%)
Conclusions: Primary syphilis was an indicator of high
HIV-1 incidence in these cities.
Although calibration of BED testing has been questioned, it is a
feasible and useful indicator of relative incidence rates in sites being evaluated
for prevention trials. Incidence of
HIV-1 appears to be lower in Lima
than in previous surveys, which may reflect widespread treatment or increased
knowledge.
|
