Country Case Studies on Sex Work and HIV Prevention 115
of those sex workers who were not trafficked and who did not agree to such enrollment. Epidemiology and Risks Factors for HIV Among Sex Workers In 1992, following a network and diffusion analysis of 488 men aged 15–50 in Ondo State, experts asserted that the slowly increasing HIV epidemic was different from what is observed in Sub-Saharan Africa. Based on this, it was assumed that the epidemic in Nigeria was not an epidemic with strong focus on sex work but likely related to the sexual diffusion within the population, despite the degree of sex work in Nigeria (Orubuloye, Caldwell et al. 1992). Since this time, however, the HIV epidemic has increased to a level that has brought Nigeria to the position of second highest number of people living with HIV worldwide and with very high HIV prevalence among sex workers in Nigeria (UNAIDS 2009). Epidemiologic assessments report a range of prevalence of HIV among sex workers in Nigeria: peer reviewed publications report a range of 37 to 70% among sex workers (Munoz, Adedimeji et al. 2010; Forbi, Entonu et al. 2011) while national figures report an overall prevalence just less than 30% among female sex workers. These figures are in stark contrast to the 3.6% prevalence that is reported among the general population (2009). Figure 3.6 presents HIV prevalence trends, comparing national estimates of women screened during ANC visits ( ) to the female sex work populations ( ) from 1991–2010. Recently, 900 female sex workers from 52 brothels in Nasarawa State were tested for HIV and incidence was estimated using the BED assay to prepare for a vaginal microbicide trial. Slightly lower than national estimates, the HIV prevalence was 37.2% among participants and, using two adjustment methods, the adjusted HIV incidence was estimated to be between 11.97% (95% CI: 8.51–15.43%) to 12.36% (8.18–16.34%) (Forbi, Entonu et al. 2011). Based on IBBSS 2010, the highest prevalence of HIV was among female brothel-based sex workers (27.4%), closely followed by non-brothel-based sex workers (27.1%) (Federal Ministry of Health [Nigeria] 2011), figures that have dropped slightly since the IBBSS 2007 (Federal Ministry of Health [Nigeria] 2008). Among the nine surveyed states (Figure 3.7) , HIV prevalence was greatest among sex workers in Benue (46.7% among brothel-based and 27.5% among non-brothel based female sex workers) and Nasarawa (46.3% among brothel-based and 32.1% among non-brothel based female sex workers) (Federal Ministry of Health [Nigeria] 2011). In Kano, where HIV prevalence