The spectrum of engagement in HIV care and its relevance to test-and-treat strategies for prevention of HIV infection

Abstract

For individuals with human immunodeficiency virus (HIV) infection to fully benefit from potent combination antiretroviral therapy, they need to know that they are HIV infected, be engaged in regular HIV care, and receive and adhere to effective antiretroviral therapy. Test-and-treat strategies for HIV prevention posit that expanded testing and earlier treatment of HIV infection could markedly decrease ongoing HIV transmission, stemming the HIV epidemic. However, poor engagement in care for HIV-infected individuals will substantially limit the effectiveness of test-and-treat strategies. We review the spectrum of engagement in care for HIV-infected individuals in the United States and apply this information to help understand the magnitude of the challenges that poor engagement in care will pose to test-and-treat strategies for HIV prevention.

Figure 1.

Health Resources and Services Administration (HRSA) continuum of HIV care, describing the spectrum of engagement in HIV care. Adapted from Eldred et al [3].

Figure 2.

The spectrum of engagement in HIV care in the United States spanning from HIV acquisition to full engagement in care, receipt of antiretroviral therapy, and achievement of complete viral suppression. We estimate that only 19% of HIV-infected individuals in the United States have an undetectable HIV load.

Figure 3.

Six simple simulations (a–f) assessing different levels of engagement in care. a, Current estimates for engagement in HIV care in the United States: 79% aware of their HIV diagnosis, 50% engaged in care (25% not linked, 25% not retained), 80% require antiretroviral therapy (ART), 75% receive ART, and 80% have an undetectable viral load while receiving ART. For the remaining simulations only the parameter(s) discussed are different. b, Assumption that 90% of HIV-infected individuals are aware of their diagnosis. c, Assumption that 90% of HIV-infected individuals who have received a diagnosis are engaged in care. d, Assumption that 90% of individuals in care receive ART. e, Assumption that viral suppression to <50 copies/mL in 90% of individuals receiving ART. f, Combination of columns b–e by assuming 90% known HIV diagnosis, 90% engagement in HIV care, 90% receipt of ART, and 90% achievement of an undetectable viral load.