Comparison of HIV Prevalence Estimates for Zimbabwe from Antenatal Clinic Surveillance (2006) and the 2005-06 Zimbabwe Demographic and Health Survey

Objective: To assess whether HIV surveillance data from pregnant women attending antenatal care (ANC) clinics in Zimbabwe represent infection levels in the general population. Methods: HIV prevalence estimates from ANC surveillance sites in 2006 were compared with estimates from the corresponding Zimbabwe Demographic and Health Survey 2005-06 (ZDHS) clusters using geographic information systems. Results: The ANC HIV prevalence estimate (17.9%, 95% CI 17.0%-18.8%) was similar to the ZDHS estimates for all men and women aged 15-49 years (18.1%, 16.9%-18.8%), for pregnant women (17.5%, 13.9%-21.9%), and for ANC attendees living within 30 km of ANC surveillance sites (19.9%, 17.1%-22.8%). However, the ANC surveillance estimate (17.9%) was lower than the ZDHS estimates for all women (21.1%, 19.7%-22.6%) and for women living within 30 km catchment areas of ANC surveillance sites (20.9%, 19.4%-22.3%). HIV prevalence in ANC sites classified as urban and rural was significantly lower than in sites classified as "other". Conclusions: Periodic population surveys can be used to validate ANC surveillance estimates. In Zimbabwe, ANC surveillance provides reliable estimates of HIV prevalence among men and women aged 15-49 years in the general population. Three classifications of ANC sites (rural/urban/other) should be used when generating national HIV estimates.