Background:  To assess the need for HIV prevention interventions it is important to assess the development of HIV incidence over time at the population level. For the design of HIV prevention interventions it is essential to know the characteristics of individuals who have recently acquired HIV. We use data from a large longitudinal HIV surveillance in a poor rural community in South Africa with high HIV prevalence to test whether HIV incidence has changed from 2003 through 2007 and to characterize recent HIV seroconverters.

Methods:  Women aged 15 to 49 and men aged 15 to 54 years were eligible for HIV testing:  8095 individuals contributed 16,256 person-years at risk and 563 seroconversions to the analysis. We did Cox regression analysis with time period at risk as a time-dependent covariate (in half-yearly increments), controlling for sex and age.

Results:  Overall HIV incidence rate was 3.4 per 100 person-years (95%CI 3.1 to 3.7). HIV incidence rate per 100 person-years was 4.4 in women and 2.1 in men (rate ratio 2.1, 95%CI 1.7 to 2.8). In women, incidence rate (per 100 person-years) increased from 4.6 (95% CI 3.6 to 5.0) in the age group 15 to 19 to a peak rate of 7.7 (95%CI 6.6 to 9.0) in the age group 20 to 24; in men, incidence rate increased from 0.6 (95% 0.4 to 1.0) in the age group 15 to 19 to a peak rate of 6.4 (95%CI 4.5 to 9.1) in the age group 25 to 29. In Cox regression, all eight half-year periods were individually insignificant (all p ≥0.387) and jointly insignificant (p = 0.701). In further analysis, we investigated the characteristics of the 563 seroconverters:  426 (or 76%) were 15 to 29 years of age; 76% were women; 61% lived in rural areas; 28% were attending school; and 19% were migrants. Of all seroconverters, 70% lived in households without any other HIV⁺ members (recently or non-recently infected) while 6% lived in households with at least one other member who seroconverted within the observation period.

Conclusions:  The study demonstrates for the first time that high levels of HIV incidence have been maintained in a rural South African community without any sign of decline over the past 5 years. It is unlikely that the HIV epidemic in rural South Africa can be reversed without new or intensified efforts to prevent HIV infection. Targeting of HIV prevention can be informed by analyses of the characteristics of recent HIV seroconverters.