South Africa could save the lives of some 4.5 million people over the next 20 years by using a double-barreled approach to HIV prevention.
That's the result of a new study by Stanford researchers who looked at two methods for helping contain the epidemic in South Africa. According to the latest figures from the United Nations Joint Programme on HIV/AIDS, South Africa is the world’s hardest-hit country with 6.1 million people infected with HIV and most new infections happening via heterosexual transmission.
Effectively targeting people who don't use condoms and have many sexual partners would prevent many infections and avert the costs of having to treat people down the road
One way to prevent sexual transmission of the disease is to give antiretroviral therapy to individuals as soon as they are found to be HIV-positive, said Sabina Alistar, PhD, first author of the new study. The World Health Organization now recommends that people go on ARV treatment when their CD4 counts – a measure of their immune system function – fall below 500. But a landmark study, published in 2011, showed that if infected individuals are effectively taking ARV treatment, the chance of their passing on the virus falls by a staggering 96 percent. So the greater the number of infected people on treatment, the less the virus will spread through the population.
“It’s much more cost-effective to put people in treatment as you find them, regardless of how far along they’ve progressed, rather than wait until they get really sick and put them on treatment,” said Alistar, who did the study while a PhD candidate in Management Science and Engineering at Stanford.
That idea isn’t new, but in this latest study from Stanford, the researchers examined the benefits of combining that universal approach to therapy with another tool, creating a powerful, cost-effective strategy for preventing millions of infections over time. The added tool, known as pre-exposure prophylaxis, or PrEP, involves daily use of a pill containing an antiretroviral drug. The pill is taken by people who may be at risk for HIV but are not infected. A landmark 2010 trial found that PrEP, if used faithfully, can reduce the risk of acquiring the virus by up to 73 percent.
“If you could focus on getting PrEP to people who engage in risky behaviors, then you could get quite significant results,” Alistar said. “Effectively targeting people who do not use condoms and have many sexual partners would prevent many infections and avert the costs of having to treat people down the road.”
She and her colleagues calculated that combining the two strategies - universal therapy for all those with HIV and targeted PrEP therapy for uninfected, high-risk individuals - would cost $150 per quality-adjusted life year gained (a QALY is measure of how much health benefit is gained for every dollar invested). That is a highly valuable bargain for South Africa, she said, which has significant resources to invest in the epidemic.
Eran Bendavid, MD, an assistant professor of medicine at Stanford and senior author of the paper, said scientists are now developing an approach to PrEP that only requires an injection every three or four months, rather than a daily pill.
When that therapy becomes available, “That has the potential to become a game-changer, since the Achilles heel of PrEP is low adherence,” Bendavid said.
The paper appears online today in the journal BMC Medicine.
Previously: U.S. AIDS Czar tells Stanford audience that witnessing death is a powerful motivator, Task force recommends HIV screening for all people aged 15 to 65, International AIDS conference ends on an optimistic note and Using family planning counseling to reduce number of HIV-positive children in Africa