Adherence: The Key Element in HIV Prevention

How do we make HIV prevention work? There’s plenty of theoretical knowledge; transforming knowledge into sustainable practice is the challenge. For longstanding biomedical prevention methods or new approaches alike, one critical component underlies sustainable HIV prevention: adherence.

We know from well-tested approaches (such as condoms and treatment) that biomedical prevention without adherence simply won’t work. Condoms have long been known as the most reliable prevention method–protecting against HIV, sexually transmitted infections (STIs), and unwanted pregnancy–but only if used every time, and correctly. As to treatment, the UNAIDS 90-90-90 goals call for people living with HIV to know their status, access antiretroviral treatment (ART), and achieve viral suppression. According to AIDSinfo guidelines, for viral suppression, adherence is indispensable; non-adherence to ART can lead to drug resistance and limit options for future treatment.

Studies on recent biomedical prevention interventions have generated excitement. Pre-exposure prophylaxis (PrEP) shows great promise for prevention in high-risk populations. Yet, for the wealth of studies showing the efficacy of PrEP, there are very few demonstrating effective adherence interventions. And using PrEP correctly is complicated. Without regular pill intake and periodic testing, PrEP users could develop resistance to the medication. For example, Haberer’s study among men who have sex with men showed that behavioral adherence interventions are essential to PrEP effectiveness.

The intravaginal ring may offer a partial response to the adherence barrier. The ring is groundbreaking in that it enables women to manage their own HIV risk, and frees them from the need to take a daily pill. This option may be especially promising for women at high risk, such as female sex workers, since it gives them the power to protect themselves without relying on a male partner to use a condom. However, even the ring requires a degree of adherence; it must remain in place for at least one month to provide sustained protection against HIV.

Decades of progress in addressing the HIV epidemic have justified high expectations and visions of universal coverage and ultimately, an AIDS-free generation. Yet within this promise lies a paradox: the fundamental ingredient of effective prevention and treatment is consistent adherence–and human beings are inconsistent by nature.

Written by Ibou Thior, Pia Kochhar, Repsina Chintalova-Dallas, and Stephanie Joyce

*Part two of this blog will discuss the numerous barriers that impede adherence.