HIV incidence in sub-Saharan Africa: a review of available data with implications for surveillance and prevention planning.

Background: HIV incidence estimation is increasingly being incorporated into HIV/AIDS surveillance activities in both resource-rich and developing countries. We conducted a systematic review to assess the availability of HIV incidence data from sub-Saharan Africa.
Methods: We examined peer-reviewed articles, conference proceedings and technical reports published from 1987-2008. Incidence estimates were classified by country, year, population group, and estimation method (prospective study or the serologic testing algorithm for recent HIV seroconversion; STARHS).
Results: Our search yielded HIV incidence estimates for 15 of 44 sub-Saharan African countries, with 57 studies generating 264 unique estimates. Of these, 239 (91%) were obtained via prospective studies, and 25 (9%) via the STARHS method (24 using the BED-CEIA assay). Only five countries reported population-based estimates, and less than two-thirds of studies reported risk factor information. STARHS use increased over time, comprising 20% of estimates since 2006. However, studies that compared STARHS estimates with prospectively observed or modeled estimates often found substantial levels of disagreement, with STARHS often overestimating HIV incidence.
Conclusions: Population-based HIV incidence estimates and risk factor information in sub-Saharan Africa remain scant but increasingly available. Regional STARHS data suggest a need for further validation prior to widespread use and incorporation into routine surveillance activities. In the meantime, prevalence and behavioral risk factor data remain important for HIV prevention planning.