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

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.

Vital Signs: Human Immunodeficiency Virus Testing and Diagnosis Delays - United States.

BACKGROUND: Persons unaware of their human immunodeficiency virus (HIV) infection account for approximately 40% of ongoing transmissions in the United States. Persons are unaware of their infection because of delayed HIV diagnoses that represent substantial missed opportunities to improve health outcomes and prevent HIV transmission. METHODS: Data from CDC's National HIV Surveillance System were used to estimate, among persons with HIV infection diagnosed in 2015, the median interval (and range) from infection to diagnosis (diagnosis delay), based on the first CD4 test after HIV diagnosis and a CD4 depletion model indicating disease progression and, among persons living with HIV in 2015, the percentage with undiagnosed infection. Data from CDC's National HIV Behavioral Surveillance were analyzed to determine the percentage of persons at increased risk for HIV infection who had tested in the past 12 months and who had missed opportunities for testing. RESULTS: An estimated 15% of persons living with HIV in 2015 were unaware of their infection. Among the 39,720 persons with HIV infection diagnosed in 2015, the estimated median diagnosis delay was 3.0 years (interquartile range = 0.7-7.8 years); diagnosis delay varied by race/ethnicity (from 2.2 years among whites to 4.2 years among Asians) and transmission category (from 2.0 years among females who inject drugs to 4.9 years among heterosexual males). Among persons interviewed through National HIV Behavioral Surveillance, 71% of men who have sex with men, 58% of persons who inject drugs, and 41% of heterosexual persons at increased risk for HIV infection reported testing in the past 12 months. In each risk group, at least two thirds of persons who did not have an HIV test had seen a health care provider in the past year. CONCLUSIONS: Delayed HIV diagnoses continue to be substantial for some population groups and prevent early entry to care to improve health outcomes and reduce HIV transmission to others. IMPLICATIONS FOR PUBLIC HEALTH PRACTICE: Health care providers and others providing HIV testing can reduce HIV-related adverse health outcomes and risk for HIV transmission by implementing routine and targeted HIV testing to decrease diagnosis delays.

Vital Signs: Trends in HIV Diagnoses, Risk Behaviors, and Prevention Among Persons Who Inject Drugs - United States.

BACKGROUND: Persons who inject drugs (PWID) are at increased risk for poor health outcomes and bloodborne infections, including human immunodeficiency virus (HIV), hepatitis C virus and hepatitis B virus infections. Although substantial progress has been made in reducing HIV infections among PWID, recent changes in drug use could challenge this success. METHODS: CDC used National HIV Surveillance System data to analyze trends in HIV diagnoses. Further, National HIV Behavioral Surveillance interviews of PWID in 22 cities were analyzed to describe risk behaviors and use of prevention services among all PWID and among PWID who first injected drugs during the 5 years before their interview (new PWID). RESULTS: During 2008-2014, HIV diagnoses among PWID declined in urban and nonurban areas, but have leveled off in recent years. Among PWID in 22 cities, during 2005-2015, syringe sharing decreased by 34% among blacks/African Americans (blacks) and by 12% among Hispanics/Latinos (Hispanics), but remained unchanged among whites. The racial composition of new PWID changed during 2005-2015: the percentage who were black decreased from 38% to 19%, the percentage who were white increased from 38% to 54%, and the percentage who were Hispanic remained stable. Among new PWID interviewed in 2015, whites engaged in riskier injection behaviors than blacks. CONCLUSIONS: Decreases in HIV diagnoses among PWID indicate success in HIV prevention. However, emerging behavioral and demographic trends could reverse this success. IMPLICATIONS FOR PUBLIC HEALTH PRACTICE: Access to comprehensive prevention services is essential for all PWID. Syringe services programs reduce syringe sharing and can help PWID access prevention and treatment services for HIV and other bloodborne diseases, such as hepatitis C and hepatitis B.