A description of HIV prevalence trends in Nigeria from 2001 to 2010: what is the progress, where is the problem?

INTRODUCTION: Nigeria's population of 160 million and estimated HIV prevalence of 3.34% (2011) makes Nigeria the second highest HIV burden worldwide, with 3.2 million people living with HIV (PLHIV). In 2010, US government spent about US$456.5 million on the Nigerian epidemic. Antenatal clinic (ANC) HIV sero-prevalence sentinel survey has been conducted biennially in Nigeria since 1991 to track the epidemic. This study looked at the trends of HIV in Nigeria over the last decade to identify progress and needs. METHODS: We conducted description of HIV sero-prevalence sentinel cross-sectional surveys conducted among pregnant women attending ANC from 2001 to 2010, which uses consecutive sampling and unlinked-anonymous HIV testing (UAT) in160 sentinel facilities. 36,000 blood samples were collected and tested. We used Epi-Info to determine national and state HIV prevalence and trends. The Estimation and Projection Package with Spectrum were used to estimate/project the burden of infection. RESULTS: National ANC HIV prevalence rose from 1.8% (1991) to 5.8% (2001) and dropped to 4.1% (2010). Since 2001, states in the center, and south of Nigeria had higher prevalence than the rest, with Benue and Cross Rivers notable. Benue was highest in 2001 (14%), 2005 (10%), and 2010 (12.7%). Overall, eight states (21.6%) showed increased HIV prevalence while six states (16.2%) had an absolute reduction of at least 2% from 2001 to 2010. In 2010, Nigeria was estimated to have 3.19 million PLHIV, with the general population prevalence projected to drop from 3.34% in 2011 to 3.27% in 2012. CONCLUSION: Examining a decade of HIV ANC surveillance in Nigeria revealed important differences in the epidemic in states that need to be examined further to reveal key drivers that can be used to target future interventions.