The United Nations Joint Program on AIDS (UNAIDS) estimates that over two million children under the age of 15 are living with HIV/AIDS in the world, with nearly 80% of these children living in sub-Saharan Africa.[1
] High levels of antiretroviral therapy (ART) adherence are critical for viral suppression and reduced morbidity and mortality among HIV infected children.[2
Through successful prevention of mother to child transmission (PMTCT) programs, developed countries face few new cases of infant HIV-infection annually; however, as a result of successful ART use, children are surviving into adolescence and struggling with many adherence challenges associated with long-term therapy. Difficulties include high rates of drug resistance due to prior treatment with suboptimal therapy, severe side effects, mental health issues, and horizontal infections among adolescents.[4
] Developing countries are confronting different challenges for achieving and maintaining ART adherence as they scale-up pediatric ART programs.[6
] Healthcare resources are typically constrained and the burden of co-morbid disease is high.
In a recent systematic review of pediatric ART adherence studies in middle- and low-income countries, Vreeman et al [7
] found that estimates of ART adherence levels ranged from 49% to 100%, with 76% of articles reporting greater than 75% adherence. The authors contrasted these values with reports from high-income countries, as summarized in another recent systematic review by Simoni et al.[8
] Estimates of pediatric adherence levels from high-income countries ranged even more widely from 20% to 100%, and 33 of 55 studies report ART adherence less than 75%. The initial high levels of adherence in developing countries are encouraging; however, adherence failures may become increasingly common as healthier children gain access and confront the long-term challenges of adherence to ART. Even with the early success, resistance levels among some children are unacceptably high.[9
] Limited availability of second-line therapy emphasizes the importance of adherence and preservation of the first-line regimen.
The goal of this paper is to help HIV clinicians and researchers conceptualize ART adherence behavior in children. It is not a systematic review of adherence studies; rather, this paper provides a framework and an evidence-based look at the factors influencing pediatric ART adherence in both developed and developing settings. It aims to improve the understanding of the complex challenges and to identify potential areas for intervention with this vulnerable population urgently in need of support.