The findings suggest that a universal “test-and-treat” strategy could be “an important addition to our toolbox of proven HIV prevention modalities,” said Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases.
The National Institute of Allergy and Infectious Diseases (NIAID)-sponsored study, Population Effects of Antiretroviral Therapy to Reduce HIV Transmission (PopART), was conducted from 2013 to 2018 in 21 urban and peri-urban communities in Zambia and South Africa, each with about 50,000 residents.
The communities were grouped as 7 “triplets” matched by geographic location and estimated HIV prevalence. The first group received annual house-to-house voluntary HIV testing and counseling, linkage to care for those testing positive, and the offer of a suite of proven prevention measures for those who tested negative. The second group received the same services as the first except treatment was offered according to national guidelines. The third group served as a control and received HIV prevention and testing services according to the local standard of care and HIV treatment according to national guidelines.
At the start of the study, the national guidelines for HIV treatment in Zambia and South Africa specified starting ART when the CD4+ T-cell count had declined to 350 cells/µL. In 2014, that threshold was raised to 500 cells/µL. In 2016, both countries recommended that everyone diagnosed with HIV begin ART immediately regardless of CD4+ T-cell count. Consequently, the first and second groups received the same intervention during the last 2 years of the study.
The researchers also recruited a random sample of about 2,300 adults from each community and visited them once a year for 3 years to collect data and test blood.
In the first 3 years, during nearly 40,000 person-years of follow-up, 553 people developed HIV infection (1.4 infections per 100 person-years). HIV incidence was 7% lower in group 1 than in the control group, although the difference was not statistically significant. However, HIV incidence was 30% lower in group 2 compared with that in the control group—a highly statistically significant and consistent result. (The researchers can’t explain why new HIV infections didn’t decline in all the communities where people who tested positive were offered immediate treatment.)
Of participants who tested positive by year 2, 72% of group 1, 68% of group 2, and 60% of the control group had achieved viral suppression.