Precaution pays: Cash incentives considered Credit: iStockphoto

An unusual HIV-prevention trial planned to take place in rural Tanzania has sparked questions from ethicists. In the proposed trial, approximately 3,000 Tanzanians between the ages of 15 and 30 are slated to receive monthly cash payments of $45 as an incentive to avoid diseases transmitted through unsafe sex. That's serious money in a nation where, in 2006, the World Bank put per capita income at $350.

Bioethicists say that any ethics committee signing off on the trial must address the question of coercion. By paying $45 monthly in a country as poor as Tanzania, “are you paying them so much that they can't refuse your offer?” asks Arthur Caplan, a bioethicist at the University of Pennsylvania in Philadelphia.

Researchers from the Ifakara Health Research and Development Centre (IHRDC) in southeastern Tanzania plan to conduct the trial in conjunction with scientists from the University of California system. On the IHRDC website, researchers trumpet the trial's “conditional cash transfers” approach as “a big advance in efforts to test public health ideas more rigorously” and note that some participants in a control arm will not be offered payments.

Testing for other sexually transmitted diseases will serve the trial as a proxy for determining HIV infection status. IHRDC researchers declined to elaborate further on the proposed trial when contacted by Nature Medicine.

The proposed three-year trial could potentially receive funding support from the World Bank. But Eric Chinje, manager of communications for the region of Africa at the World Bank, says that the institutions involved are still assessing the trial and “there is no consensus on its viability.”

Karen Maschke, who focuses on ethics and science policy at the Hastings Center in Garrison, New York, points out that the behavior being encouraged by the payments is not entirely risk-free: “In some conditions, you are putting women at risk [of violence] for demanding safety during sex.”

Bioethicist Stuart Rennie of the University of North Carolina at Chapel Hill agrees that the trial raises a list of issues, including the practical concern of how to keep a new infection confidential in a family counting on the income from the trial. Still, he says, the trial has clinical promise: “I think they should pilot it.”

There is some precedent for cash incentive programs, albeit not involving sexual practices: In Mexico in the late 1990s, a government-sponsored program boosted class attendance significantly by offering cash rewards to poor families that sent their children to school. And, in the United States, a growing number of states provide financial incentives to encourage people receiving Medicaid to use preventive services and combat smoking and obesity. Whether these US interventions are effective, however, has not been proven in rigorous studies.