Estimating HIV Incidence Rates among MSM in an Urban Area of Chongqing Using Three Approaches.

To evaluate the HIV pandemic in Chongqing, the pooled PCR, IgG-capture BED enzyme immunoassay (BED-CEIA), and cohort observations were used to estimate the HIV incidences among men who have sex with men (MSM). 617 MSM subjects completed the survey at a voluntary counseling and testing (VCT) site. The observed HIV incidence was 12.5 per 100 P-Ys (95% CI = 9.1-15.7). The annual acute HIV infection (AHI) incidence estimated by pooled PCR was 14.0% (95% CI = 10.9-17.1). The HIV-1 annual incidence estimated based on the BED-CEIA was 12.0% (95% CI = 7.5-16.5). The HIV incidences estimated by these three approaches were consistent and complementary. The HIV incidence rates were alarmingly high with an uptrend among the urban MSM of Chongqing.