In the past few months, support for HIV pre-exposure prophylaxis (PrEP; Truvada) has grown substantially. The CDC and WHO now endorse it, as does New York State Governor Cuomo who recently announced a multi-pronged plan to reduce the rate of new HIV infections in the state by 75% before 2020. However, the role of PrEP in curbing HIV transmission is still hotly debated – who should take it, who should pay for it, and whether or not it will work on a population level. Its price tag is about $10,000/year to insurers, it requires daily adherence for maximum benefit, and involves periodic testing to monitor a patient’s HIV status. Part of the concern is that PrEP’s effectiveness may be affected by two behavioral phenomena often experienced in health promotion: self-selection and risk compensation.
Self-selection is, in this case, when those who are more at risk (based on behavior) may not realize this and be less likely to seek out the drug. Self-selection is commonly seen in health promotion programs – where those who need an intervention the most are often the hardest to reach – but it can be surmounted by lowering the stigma around HIV testing and treatment, potentially through financial incentives for testing or medication adherence.
Risk compensation occurs when those who take a preventive measure engage in riskier behaviors because of a perceived level of protection. Though risk compensation was not observed in the landmark iPrEX study, this is still a potential hazard. Interesting parallels can be drawn to the experience where those on statins continued to eat a worse diet and gain weight.
To ensure success in health promotion and specifically, HIV prevention, targeted programs must reach out to those least likely to engage, normalize HIV testing and PrEP use, and strengthen the structural ties between testing and follow-up with PrEP or treatment. If this happens, more people will be aware of their HIV status (nationally there are 50,000 new cases of HIV annually but 20% do not know they are HIV-positive); there will be increased “herd immunity” to prevent the spread of the virus; and because more people will be in contact with the medical system, there can be increased counseling about sexual health (including condom use) and other prevention measures for overall healthier lifestyles.