Vital Signs: HIV Transmission Along the Continuum of Care - United States, 2016

Abstract

Background: In 2016, an estimated 1.1 million persons had human immunodeficiency virus (HIV) infection in the United States; 38,700 were new infections. Knowledge of HIV infection status, behavior change, and antiretroviral therapy (ART) all prevent HIV transmission. Persons who achieve and maintain viral suppression (achieved by most persons within 6 months of starting ART) can live long, healthy lives and pose effectively no risk of HIV transmission to their sexual partners.

Methods: A model was used to estimate transmission rates in 2016 along the HIV continuum of care. Data for sexual and needle-sharing behaviors were obtained from National HIV Behavioral Surveillance. Estimated HIV prevalence, incidence, receipt of care, and viral suppression were obtained from National HIV Surveillance System data.

Results: Overall, the HIV transmission rate was 3.5 per 100 person-years in 2016. Along the HIV continuum of care, the transmission rates from persons who were 1) acutely infected and unaware of their infection, 2) non-acutely infected and unaware, 3) aware of HIV infection but not in care, 4) receiving HIV care but not virally suppressed, and 5) taking ART and virally suppressed were 16.1, 8.4, 6.6, 6.1, and 0 per 100 person-years, respectively. The percentages of all transmissions generated by each group were 4.0%, 33.6%, 42.6%, 19.8%, and 0%, respectively.

Conclusion: Approximately 80% of new HIV transmissions are from persons who do not know they have HIV infection or are not receiving regular care. Going forward, increasing the percentage of persons with HIV infection who have achieved viral suppression and do not transmit HIV will be critical for ending the HIV epidemic in the United States.

FIGURE 1

Percentage of persons with human immunodeficiency virus (HIV) infection and transmissions along the continuum of HIV care — United States, 2016^§,¶ Abbreviation: ART = antiretroviral therapy. * Percentage of persons in each subgroup averaged over 12 months in the model. ^† Receipt of medical care was defined as one or more tests (CD4 or viral load) in 2015. ^§ Viral suppression was defined as <200 copies of HIV/mL of blood on the most recent viral load test. ^¶ Unaware of HIV infection includes acutely infected and non-acutely infected persons unaware of their HIV infection.

FIGURE 2

Percentage of persons with human immunodeficiency virus infection (HIV) who are virally suppressed and HIV transmission rate — United States, 2010–2016 * Viral suppression among persons with HIV infection; percentage obtained by multiplying the percentage with infection by the percentage virally suppressed among persons with diagnosed HIV. Viral suppression was defined as <200 copies of HIV/mL of blood on the most recent viral load test. ^† Generated from model. Measured in number of transmissions per 100 person-years (i.e., annual number of transmissions from 100 persons). ^§ 2016 viral suppression data is not yet available.