The study had an interesting design. The Hlabisa subdistrict in northern KZN was divided into 22 geographic zones, each of about 1,280 people aged 16 years or older. These 22 zones were randomly divided into two groups of 11 zones each. In both groups people were offered HIV testing in their homes every six months. In one group, known as the intervention arm, people with HIV were offered antiretroviral treatment immediately. In the other group, known as the control arm, people with HIV were offered treatment only when they met the Department of Health’s criteria to start treatment. The study ran from March 2012 to June 2016. It was anticipated that in the intervention population, there would be fewer new HIV infections, at least one-third less.
A total of 495 people out of the approximately 28,000 people in the geographic zones that were part of the study contracted HIV. But in the intervention arm the infection rate (also known as incidence) was 2.13% per year versus 2.27% in the control arm after 18 months. This difference is considered insignificant because it could be due to chance.