Estimating HIV-1 incidence using the serologic testing algorithm for recent HIV infections at HIV counseling and testing centers in the city of São Paulo, Brazil

ABSTRACT

The network of HIV counseling and testing centers in São Paulo, Brazil is a major source of data used to build epidemiological profiles of the client population. We examined HIV-1 incidence from November 2000 to April 2001, comparing epidemiological and socio-behavioral data of recently-infected individuals with those with long-standing infection. A less sensitive ELISA was employed to identify recent infection. The overall incidence of HIV-1 infection was 0.53/100/year (95 percent CI: 0.31-0.85/100/year): 0.77/100/year for males (95 percent CI: 0.42-1.27/100/year) and 0.22/100/ year (95 percent CI: 0.05-0.59/100/year) for females. Overall HIV-1 prevalence was 3.2 percent (95 percent CI: 2.8-3.7 percent), being 4.0 percent among males (95 percent CI: 3.3-4.7 percent) and 2.1 percent among females (95 percent CI: 1.6-2.8 percent). Recent infections accounted for 15 percent of the total (95 percent CI: 10.2-20.8 percent). Recent infection correlated with being younger and male (p = 0.019). Therefore, recent infection was more common among younger males and older females.