Longitudinal surveillance of a poor rural community in Kwazulu-Natal, South Africa, indicates that HIV incidence remained high from 2003 through 2007, despite prevention activities in the region, with almost half of all new infections occurring in people who had already received one negative test result through local voluntary testing and counselling services.
The study, conducted by the Africa Centre for Health and Population Studies of the University of KwaZulu-Natal, reported the latest findings of an extensive research effort to track the impact of HIV on a hard-hit rural area in northern Kwazulu-Natal, the Hlabisa district. Although bisected by a major highway, Hlabisa is largely agricultural, with high levels of unemployment.
Previous results from this study were presented at the ">South African AIDS Conference in 2007
The study population included women aged 15 to 49 and men aged 15 to 54, recruited through a household census survey.
Five hundred and sixty-three seroconversions occurred among 8095 people during 16,256 person-years of risk. This represents an overall HIV incidence rate of 3.4 per 100 person-years (95% confidence interval [CI], 3.1 – 3.7.) Women had an incidence rate of 4.4 per 100 person-years and men had an incidence rate of 2.1 per 100 person-years.
The incidence rate per 100 person-years increased from 4.6 in women aged 15 to 19 (95% CI, 3.6 – 5.0) to 7.7 in women aged 20 to 24 (95% CI, 6.6 – 9.0). For men, there was an increase from 0.6 in the group aged 15 to 19 (95% CI, 0.4 – 1.0) to 6.4 in the group aged 25 to 29 (95% CI, 4.5 – 9.1).
When the researchers looked at changes over time in HIV incidence they were unable to find any significant changes in HIV incidence between 2003 and 2007 – the rate of new infections essentially remained stable, despite HIV prevention activities taking place in the locality.
Seventy-six percent of the 563 seroconverters were women; 61% lived in rural areas; 28% were attending school; and 19% were migrants. Till Barnighausen of the Africa Centre, reporting the results, noted that 80% of seroconversions occurred in people under the age of 30.
Fifty per cent of seroconverters reported having attended a voluntary counselling and testing (VCT) service at least once before subsequently serocoverting, suggesting that post-test counselling may not be having the expected impact on sexual behaviour in those who test negative (this finding is consistent with several studies of the impact of VCT in southern Africa, which show a significant impact of VCT on subsequent sexual behaviour only in those who test HIV-positive).
Twenty-four percent of seroconverters reported living in households which had included at least two other HIV-positive members at some time point, indicating the very high impact of HIV in the locality. Six percent reported living in households where at least one other household member seroconverted within the observation period. Thirty-two per cent said they knew someone taking antiretroviral therapy, but 32% of seroconverters didn’t know about antiretroviral therapy.
The high rate of seroconversions in young people indicated a need to reach young people while still at school, said Till Barnighausen, but he acknowledged that recent results from a large study of school-based HIV prevention in Tanzania, which showed a lack of effect on HIV incidence in under-25s despite seven years of school- and community-based activity, made it difficult to define what interventions are likely to have an impact at the population level in settings where HIV incidence remains high.
Barnighausen T et al. HIV incidence time trend and characteristics of recent seroconverters in a rural community with high HIV prevalence: South Africa. Sixteenth Conference on Retroviruses and Opportunistic Infections, Montreal, abstract 173, 2009.