Test-and-treat package for HIV prevention trialled in South Africa and Zambia

Project staff in Zambia learn to use a portable diagnostic appliance. Photo: ZAMBART

Researchers at Imperial College London are contributing to a major study testing a combination of measures to prevent HIV in South Africa and Zambia.

The study will assess whether house-to-house voluntary HIV testing and prompt treatment of HIV infection, along with other proven HIV prevention measures, can substantially reduce the number of new HIV infections across communities.

The trial, Population Effects of Antiretroviral Therapy to Reduce HIV Transmission (PopART), or HPTN 071, will build on the results of a previous trial, which found that HIV-infected individuals who start treatment early, when their immune systems are relatively healthy, dramatically reduce the risk of transmitting the virus to their heterosexual partners.

The trial is being conducted in South Africa and Zambia because the HIV prevalence in those countries is among the highest in the world. An estimated 12.5 per cent of adults in Zambia and 17.3 per cent of adults in South Africa are infected.

The  HIV prevention package being trialled includes:

• Door-to-door, voluntary HIV testing offered at annual intervals
• Helping people who test positive for the virus access care at local health centres
• Promotion of voluntary medical circumcision to men who are not HIV-infected
• Promotion of steps to prevent mother-to-child HIV transmission
• Referral of individuals with other sexually transmitted infections to treatment
• Provision of condoms

Leading the study are Richard Hayes, professor of epidemiology and international health at the London School of Hygiene and Tropical Medicine, and Dr Sarah Fidler, from the Department of Medicine at Imperial College London. Professor Christophe Fraser’s group, at the Medical Research Council Centre for Outbreak Analysis and Modelling at Imperial, is leading the mathematical modelling analysis, and Professor Peter Smith at Imperial College Business School will direct the economics and cost effectiveness analysis, information that is critical to inform policy makers.

Dr Fidler said: “This study is the largest community randomised trial in areas of Africa that have some of the highest HIV prevalence worldwide.

“There is now clear trial data confirming that the use of antiretroviral therapy can significantly reduce the risk of transmission through sex or from infected mothers to their infants. But it’s uncertain how best to get treatment to the communities most affected by the epidemic, where resources for staff and treatment are often limited and the stigma and discrimination against those people living with HIV is a huge problem.

“This trial will explore the operational questions about how such a universal voluntary HIV testing campaign, in combination with a package of prevention tools, can impact the number of new infections at a population level. The findings will inform policy makers on future HIV prevention approaches with the goal of ending the epidemic for the next generation.”

Professor Fraser said: "The PopART trial aims to test whether the extraordinary promise of early antiretroviral treatment to suppress transmission that has been found in controlled trials can be translated into real benefits in the field.

“We hope this will prevent many new infections. We will generate evidence that will inform difficult decisions regarding this potentially game-changing but very expensive policy.

“My group will be developing detailed computer simulations that will help us understand what happens in the trial, and extrapolate the findings to other settings and longer time frames."

The PopART trial will involve 21 communities in South Africa and Zambia with a total population of 1.2 million. The study team has randomly assigned each community to one of three groups. One group of communities will receive the HIV prevention package along with the opportunity for HIV-infected individuals to begin treatment as soon as they test positive for the virus. The second group will receive the same HIV prevention package, and infected individuals will be offered treatment at the stage of infection recommended by their country’s HIV treatment guidelines. The third group will serve as a control and will receive existing HIV prevention and testing services along with HIV care and treatment according to current national guidelines for their country.

The study team will measure the impact of the two HIV prevention packages by determining the number of new HIV infections among a representative sample of 52,500 adults drawn from the 21 study communities and followed for three years. The study is expected to end in 2019.

The study is being conducted by the National Institutes of Health-funded HIV Prevention Trials Network (HPTN). The study is led by investigators at the London School of Hygiene and 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.  The study is sponsored by NIH’s National Institute of Allergy and Infectious Diseases (NIAID), with funding from U.S. President's Emergency Plan for AIDS Relief (PEPFAR). PEPFAR partners will provide HIV care and treatment to the study communities under the direction of the U.S. Agency for International Development and the U.S. Centers for Disease Control and Prevention.

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, all part of NIH.

For more information about this study, there is a Q&A provided by NIAID.