Discussion

This analysis revealed large differences in rates of diagnosis of HIV infection with increasing age among persons aged 13–15, 16–17, 18–19, and 20–21 years. This report also documents trends in diagnoses during 2010–2014 by narrow age groups, with increasing rates observed among persons aged 24–25 and 26–27 years and decreasing rates among persons aged 16–17, 18–19, and 20–21 years.

Studies focused on adolescents and young adults with HIV infection commonly incorporate broader age ranges (e.g., 13–29 years), obscuring important distinctions that can contribute to a better understanding of HIV infections among persons during adolescence and into young adulthood (4). Adolescence and young adulthood are periods of considerable biologic and physiologic change and represent developmental phases when engagement in high-risk sexual behaviors and alcohol and other drug use peak and the risk for acquiring HIV infection increases (4,5). However, few HIV-related studies have taken into account these developmental transitions, and studies rarely include persons aged <18 years (5). A recent longitudinal study in an urban area with high HIV prevalence among men aged 16–20 years who have sex with men found that HIV incidence was just as high among participants aged <18 years as among older participants (5), highlighting the importance of including adolescents aged <18 years in research and prevention efforts, particularly HIV testing. A previous study has also shown delays in diagnosis of HIV infection of an average of 2.7 years in persons aged 13–24 years (2), indicating that the period of risk for HIV acquisition begins before age 18 years.

To help address the impact of HIV infection among adolescents and young adults, especially sexual and racial/ethnic minority populations, two national goals focus on persons aged 13–24 years as a priority population at risk to monitor the percentage of young gay and bisexual men who have engaged in HIV acquisition risk behaviors and the percentage of adolescents and young adults with diagnosed HIV infection who are virally suppressed (<200 HIV RNA copies/mL) through use of antiretroviral therapy (6). Unfortunately, adolescents and young adults are least likely to be linked to and retained in HIV care or to achieve viral suppression (7,8). In 2014, among men who have sex with men, who account for the majority of persons with HIV infection among persons aged 13–24 years, 48% were aware of their infection; awareness of infection is crucial to health and prevention (9). Among persons aged 13–24 years with infection diagnosed in 2014, 68% were linked to HIV medical care within 1 month of diagnosis, and among those living with diagnosed HIV infection at the end of 2013, 55% were retained in care, and 44% were virally suppressed (8). All of these indicators are well below national targets (9). Additional studies are needed to identify barriers that affect testing, retention in care, and access to health services, including the use of preexposure prophylaxis, among adolescents and young adults, particularly persons aged <18 years (6,7).

The findings in this report are subject to at least three limitations. First, the data presented reflect diagnoses of HIV infection, which are subject to diagnosis delay when compared with incidence, and are not necessarily representative of all persons with HIV infection. Whereas there are models available to estimate incidence, such approaches typically yield wide confidence intervals and unreliable estimates for narrow age groups. Second, trends in diagnoses of HIV infection might be attributed to changes in testing, transmission, or reporting. Finally, state laws affecting minors’ consent to care and disparities in access might also affect testing behaviors.

These findings underscore the importance of targeting primary prevention efforts to persons aged <18 years, specifically those aged 16–17 years, and continuing through the period of elevated risk in the mid-twenties. Much remains to be understood about the factors that affect adolescents and young adults at high risk for acquiring or transmitting HIV infection. CDC supports school districts and state education agencies that promote environments where teens can gain fundamental health knowledge and skills, establish healthy behaviors for a lifetime, connect to health services, and avoid becoming pregnant or infected with HIV or other sexually transmitted diseases (10). When implementing effective HIV prevention strategies, a multifaceted approach that incorporates the educational, social, policy, and health care systems can help support youths as they transition from adolescence into young adulthood (7).