Trends in the HIV epidemic in Angola, 2004-2007

BACKGROUND: According to the 2010 UNAIDS Report on the Global AIDS Epidemic, to date, Angola has experienced a relatively limited HIV epidemic (HIV prevalence estimate, 2.0%). METHODS: To better understand the Angola HIV epidemic, we used existing information and applied secondary analysis to data collected at sites (n=22) consistently sampled for three of the four national antenatal clinic HIV/syphilis/hepatitis B sentinel serosurveys performed in Angola to date (2004, 2005 and 2007). Multivariate logistic regression models were used to assess HIV prevalence trends and potential individual-level (e.g., demographics) and provincial-level (e.g., international borders, and major truck routes and stops) predictors of HIV infection. RESULTS: Data for 10,805 (2004), 10,970 (2005), and 10,848 (2007) participants were available for analysis. Socio-demographic factors were similar across the three surveys. Median HIV prevalence (2007) was 2.6% (provincial range 0.6%-9.4%). Statistically significant and independent risk factors for HIV infection included age groups > 25 years, unwedded marital status, and educational levels of US equivalent 5th-6th and 7th-12th grades. Longitudinal (2004-2007) HIV prevalence trends among pregnant women 15-24 and 15-49 years, however, were not statistically significantly different. CONCLUSIONS: The analysis presented confirms a low overall HIV prevalence in Angola between 2004 and 2007, but with wide provincial variation, and preferentially affecting certain survey sub-populations. Sentinel surveillance has greatly informed HIV policy in Angola, particularly in the roll-out of interventions in discreet geographical areas where HIV prevalence rates can be almost four times the national prevalence; however, a better characterization of the risk of and vulnerability to HIV infection is needed. Geographic-specific integrated bio-behavioral surveillance among sub-groups of men and women should be considered to better inform prevention interventions and specific services while HIV prevalence remains relatively low in some parts of the country.