London School of Hygiene & Tropical Medicine

The Population Effects of Antiretroviral Therapy to Reduce HIV Transmission study, (PopART, also known as HPTN 071) will determine the impact of a combined package of HIV prevention measures in reducing the number of new HIV infections.

The study is being carried out by the London School of Hygiene & Tropical Medicine in collaboration with the HIV Prevention Trials Network (HPTN) and other partner organisations. It involves 21 communities in South Africa and Zambia with a total population of 1.2 million people.

The combined HIV prevention package being assessed includes a universal test-and-treat approach, with door-to-door voluntary testing for all households and the offer of immediate antiretroviral therapy (ART) treatment for all HIV-infected adults as soon as they are diagnosed. This means that HIV-positive individuals are identified at a much earlier stage and can start treatment straight away. Currently individuals only qualify for treatment with ART drugs at the stage of infection recommended by their country’s HIV treatment guidelines.

Recent clinical trials have demonstrated that measures included in the combination prevention package can be effective. While most of these prevention approaches are now offered in many settings with high rates of HIV, achieving high enough coverage to reduce the number of new infections has proven challenging. The PopART study aims to deliver the prevention package to all households within a community to enhance coverage and thereby reduce new HIV infections at the population level. Specially trained community health workers will play a key role in achieving high coverage for these measures.

Richard Hayes, PopART Principal Investigator and Professor of Epidemiology and International Health at the London School of Hygiene & Tropical Medicine, said: “There is a very strong rationale for test-and-treat as a new approach to HIV prevention. Mathematical models indicate that if a high proportion of a population can be tested for HIV, and those found to be infected are offered treatment right away, then the rate of new HIV infections could decrease substantially over time.

“The PopART study is assessing whether this approach can be delivered on a wide scale in sub-Saharan Africa with high uptake and coverage, and what impact this will have on HIV incidence at the population level.”

The PopART study builds upon previous research that supports the argument for this prevention approach. Previous trials (HPTN 052 and HPTN 043) have shown that treating an HIV-infected individual with ART can significantly reduce the risk of sexual transmission of the virus to an uninfected partner, and that providing community mobilisation and mobile HIV counselling and testing can improve rates of testing in rural communities, compared to settings where testing only takes place at clinics.

The communities taking part in the PopART trial were randomly assigned to one of three groups (arms) in a public randomisation ceremony earlier this year. The seven communities in Arm A will be offered the full HIV intervention package, including the opportunity for HIV-infected individuals to begin treatment as soon as they are diagnosed with the virus. The second group of seven communities (Arm B) will receive the full package, but this time with ART treatment only offered according to current national guidelines based on the stage of the infection. The remaining seven communities in Arm C will receive current standards of care for both testing and treatment according to the national guidelines of their country.

To measure the impact of these different interventions, a representative sample of 2,500 adults will be recruited from the general population of each community (a total of 52,500 across all 21 communities) and will be followed up annually for three years. The occurrence of new HIV infections in these communities will be compared between the three study arms to determine the effect of the PopART interventions.

The full PopART HIV prevention package that will be offered includes:

• House-to-house voluntary HIV testing offered at annual intervals
• Linkage of HIV-infected individuals to HIV care
• Promotion of voluntary medical circumcision for HIV-uninfected men
• Promotion of steps to prevent mother-to-child HIV transmission
• Referral of individuals with symptoms suggestive of TB or sexually transmitted infections for diagnosis and care at the local health centre
• Provision of condoms

The PopART findings will determine whether such an HIV prevention package will work at population level and whether it is cost effective, and will provide evidence for policymakers to develop HIV control policies in many other countries.

The study comprises investigators from at the London School of Hygiene & Tropical Medicine in collaboration with Imperial College London, the Zambia AIDS Related Tuberculosis Project (ZAMBART) and the Desmond Tutu TB Centre at Stellenbosch University, South Africa.

It is sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health (NIH), with funding from the US President’s Emergency Plan for AIDS Relief. Additional funding is provided by the International Initiative for Impact Evaluation with support from the Bill & Melinda Gates Foundation, as well as by NIAID, the National Institute on Drug Abuse and the National Institute of Mental Health.