The HIV care continuum: no partial credit given.

Despite significant scale-up of HIV care and treatment across the world, overall effectiveness of HIV programs is severely undermined by attrition of patients across the HIV care continuum, both in resource-rich and resource-limited settings. The care continuum has four essential steps: linkage from testing to enrollment in care, determination of antiretroviral therapy (ART) eligibility, ART initiation, and adherence to medications to achieve viral suppression. In order to substantially improve health outcomes for the individual and potentially for prevention of transmission to others, each of the steps of the entire care continuum must be achieved. This will require the adoption of interventions that address the multiplicity of barriers and social contexts faced by individuals and populations across each step, a reconceptualization of services to maximize engagement in care, and ambitious evaluation of program performance using all-or-none measurement.