Researchers at Stanford University have argued that efforts to prevent HIV with limited resources should prioritize the scaling-up of treatment for the virus over using Truvada (tenofovir/emtricitabine) as pre-exposure prophylaxis (PrEP), and that investment in effective community-based education (CBE) should be prioritized over scaling up treatment. Publishing their findings in Medical Decision Making, the investigators developed a linear model to determine the optimal mix of investments in HIV treatment and prevention in the event of a fixed budget.

The model took into account the secondary health benefits of HIV treatment—secondary in this case because the researchers were focusing on prevention matters—as well as prevention among MSM.

Research suggests that HIV-positive people who maintain an undetectable viral load have a dramatic reduction in their risk of transmitting the virus to others. Meanwhile, HIV-negative people who adhere well to a daily regimen of Truvada as PrEP benefit from similarly high levels of reduction in risk for acquiring the virus. (This new study used for its calculations the 44 percent population-level effectiveness rating for PrEP found in the 2010 iPrEx study, in which average adherence levels among the participants were quite poor.)

In all the scenarios they ran, the researchers concluded that prioritizing investment in HIV treatment over PrEP was optimal. Treating HIV, they reasoned, always offers a greater ratio of benefits to cost when compared with PrEP.

“PrEP is a much less efficient use of resources than is [treatment] scale-up,” the authors wrote. “Even with high PrEP [population-level] efficacy or in a rapidly growing epidemic, factors that could tip the scales toward [prioritizing] prevention, PrEP is a much less efficient use of resources than is [HIV treatment] scale-up.”

If CBE reduced risky behavior by 4 percent or less, investing in ART before CBE was optimal, the researchers found. But if CBE were more effective, such efforts should be prioritized over treatment.

“For MSM in the US,” the authors concluded, “HIV control funds should be prioritized on inexpensive, effective programs like CBE, then on [HIV treatment] scale-up, with only minimal investment in PrEP.”

To read the study abstract, click here.

To learn about a study looking at the cost-effectiveness of PrEP among MSM, click here.