We know that adherence is the key to prevention and treatment. But how do we ensure adherence in the face of the myriad individual, structural, financial, psychological, and social barriers that HIV-positive people need to overcome?
Ever-improving biomedical approaches have yet to solve the problem of adherence. Ultimately, it’s likely that achieving adherence will mean returning to the question of human behavior—because it’s the human factors that make or break adherence.
Think of the typical patterns of condom use. As Part 1 mentions, condoms are only effective if used correctly, every time. Evidence shows that newer partners are more likely to use condoms. But once the partners trust each other (and thus perceive less risk), consistent use decreases—especially when alcohol or drugs are involved.
Barriers stemming from human behavior also hinder adherence to newer and potentially powerful biomedical approaches. Activists are enthusiastic about the potential of the intravaginal ring for women’s empowerment and protection. Yet if the ring proves uncomfortable for either the woman or her partner, or if it proves difficult to change the ring every month, women may stop using it.
Pre-exposure prophylaxis (PrEP) also promises substantial protection for high-risk groups. But PrEP is expensive—many governments can’t afford it. It can also cause potentially unpleasant side effects. Also, adherence to PrEP requires follow-up for HIV testing at least every three months before prescriptions are refilled or reissued for patient safety. During this critical period of PrEP use, a number of factors (travel difficulties, financial problems, conflicting work schedules, or user errors, such as forgetting a dose) can interfere with adherence.
As importantly, the fear of stigma—of being seen going into an HIV clinic—can potentially derail adherence to PrEP or any other approach to prevention and treatment.
Despite all these barriers, we do know it’s possible to achieve broad adherence using a wide range of approaches, from top-down to grass-roots. A famous top-down example from the early 1990s is Thailand’s 100 % Condom Program, which required brothels to consistently use condoms or face closure. The result, according to WHO, was a decrease in the rate of new infections from 143,000 a year to 14,000 a year over 10 years. The change in Brazil’s HIV prevalence, by contrast, was bottom-up. Nongovernmental and human rights groups demanded action against social exclusion and stigma against those living with HIV. Responding to this public pressure, the Brazilian government launched a number of effective programs, including extensive condom distribution, free and generic antiretroviral drugs, and needle exchanges for drug users. According to the American Journal of Public Health, HIV-related mortality rates fell 50 percent between 1995 and 2005.
While macro-level changes, such as shifts in government priorities and access to funding, limited the sustainability of these national-level programs, studies continue to document examples of successful adherence interventions at the community level. A recent study on community-based adherence clubs in South Africa found that 94 percent of patients attending these clubs were retained in antiretroviral therapy after 12 months.
Adherence is a complex equation that requires a balance between individual compliance and enabling factors in the individual’s environment. New prevention approaches—long-acting vaginal rings, long-acting injectable PrEP, and even the promise of a vaccine—generate excitement because they address some of the adherence challenges that have been hampering HIV prevention and treatment efforts. Even so, behavior remains central to the concept of an AIDS-free generation.