Abstract
Three decades after the emergence of HIV, we have made great strides in our response to the epidemic, from prevention of transmission to testing and treatment. However, it is still common in high-prevalence settings for people to not know their HIV status, and estimates are that globally, a mere 36% of those eligible for treatment are receiving it. On top of this, for every person with HIV entering treatment, two more are infected. The operational obstacles to overcoming the challenges and fully implementing proven strategies are numerous. The operational research and implementation sciences aim to provide a sound basis for how to maximize the use of limited resources by investigating the best models to deliver services and implement programmes in various settings and contexts. In this special issue, the Journal of the International AIDS Society intends to highlight some of the operational and programmatic challenges that are faced in sub-Saharan Africa, home to the largest population living with HIV. Our hope is that readers gain insight into some of the challenges associated with the HIV/AIDS epidemic and a changing environment in the region, and become familiar with some applications of operational research and implementation science in HIV healthcare settings.