Comparison of HIV Prevalence Estimates From Sentinel

Comparison of HIV Prevalence Estimates From Sentinel Surveillance and a National Population-Based Survey in Uganda, 2004-2005. J Acquir Immune Defic Syndr. 2009 May;51(1):78-84.

HIV programs in generalized epidemics have traditionally relied on antenatal clinic sentinel surveillance data to guide prevention and to model epidemic trends. Antenatal clinic data, however, come from a subset of the population, and their representativeness of the population has been debated. Musinguzi and colleagues compared data from a national population-based Uganda HIV Sero-Behavioral Survey with those from antenatal clinic sentinel surveillance. Using geographic information system, Uganda HIV Sero-Behavioral Survey clusters within a 30 km radius of the antenatal clinic sites were mapped. Estimates of HIV prevalence from antenatal clinic surveillance were compared with those from Uganda HIV Sero-Behavioral Survey. They found that the antenatal clinic-based HIV prevalence, 6.0% [confidence interval (CI) 5.5% to 6.5%], was similar to that from Uganda HIV Sero-Behavioral Survey, 5.9% (CI 5.4% to 6.4%). The antenatal clinic-based estimate correlated with that of Uganda HIV Sero-Behavioral Survey catchment area women who were pregnant and those who had given birth in the 2 years preceding the survey. Antenatal clinic data overestimated prevalence in the 15-year to 19-year age group, were similar to Uganda HIV Sero-Behavioral Survey for ages 20-29 years, and underestimated prevalence in older respondents. Antenatal clinic data underestimated HIV prevalence among women (6.0% vs. 7.4%; CI 6.6% to 8.2%) and urban women (7.6% vs. 12.7%) but was similar for rural women (5.3% vs. 4.9%). Antenatal clinic -based surveillance remains an important tool for monitoring HIV programs. Antenatal clinic and Uganda HIV Sero-Behavioral Survey data were similar overall and for 15-year to 29-year olds, women who were pregnant, and women who had a birth in the 2 years before the survey. Antenatal clinic estimates were lower in those >/=30 years and in urban areas. Periodic serosurveys to adjust antenatal clinic -based estimates are needed.

Editors’ note: In a mature epidemic such as Uganda’s, antenatal surveillance is likely to underestimate HIV prevalence in older women because older women can be at significant risk of acquiring HIV after the reproductive age and women with HIV who are of reproductive age tend to have lower fertility. Antenatal surveillance does generally reflect the general population prevalence among 15 to 29 year olds and in the age group 15 to 19 years it can be used as a general proxy measure of HIV incidence. Thus, antenatal clinic surveillance, supplemented by periodic population-based sero-behavioural surveys to provide an adjusted picture of national HIV epidemics, remains a valid surveillance tool.