Background From 2001 to 2009 the estimated number of adults and children living with HIV in Nicaragua nearly doubled from 3700 to 6900. In Central America, the HIV epidemic is primarily concentrated in a few populations, including female sex workers (FSWs), who also bear a substantial burden of other sexually transmitted infections (STIs). This study reports results from the Central American Surveillance Survey of Sexual Behaviour and Prevalence of HIV/STIs in Vulnerable Populations, which was conducted among FSWs in Nicaragua in 2009.

Methods We conducted a comprehensive sampling of FSWs in the Nicaraguan cities of Managua (N=618) and Chinandega (N=214) in 2009. Utilising a behavioural surveillance survey (BSS) approach within the framework of second generation HIV surveillance, we conducted a cross-sectional evaluation of HIV prevalence and incidence, prevalence of other STIs, and relevant behavioural and contextual factors.

Results Estimated HIV prevalence among FSWs was 1.8% (95% CI 0.9% to 3.2%) in Managua and 2.4% (95% CI: 0.8% to 5.4%) in Chinandega. Estimated annual HIV incidence among all participating FSWs was 0.8% (95% CI: 0.0% to 2.0%). In Managua 36.5% of FSWs (95% CI: 32.7% to 40.5%) and in Chinandega 51.4% of FSWs (95% CI: 44.5% to 58.3%) had received an HIV test in the 12 months prior to the study. Substantial prevalence of infection with herpes simplex virus type 2 (HSV-2) was found among FSWs in both Managua (75.7%; 95% CI: 72.1% to 79.0%) and Chinandega (83.5%; 95% CI: 77.8% to 88.2%). All FSWs with HIV infection also had HSV-2 infection. Considerable but variable prevalence of other STIs was also present among FSWs participating in the study (Abstract O1-S08.04 table 1). Consistent condom use during the previous 30 days among FSWs varied markedly according to type of sexual partner, and was highest with clients (89.9%; 95% CI: 87.5% to 91.7%), lower with occasional partners (61.0%; 95% CI: 50.9% to 70.3%), and lowest with stable partners (12.7%; 95% CI; 9.7% to 16.3%).

Conclusions Our estimate of HIV prevalence among FSWs in Managua is higher than the 0% (97.5% CI: 0.0% to 1.1%) HIV prevalence reported for this population in the 2001–2002 Estudio Multicéntrico. Similarly, we report an annual HIV incidence estimate that is higher than the 0% annual HIV incidence reported in the 2001–2002 study. Compared to the Estudio Multicéntrico, we found slightly higher rates of consistent condom use with stable partners, and substantially higher rates of consistent condom use with clients.