Demographic change and HIV epidemic projections to 2050 for adolescents and young people aged 15-24.

: Ending AIDS as a public health threat by 2030 is a significant challenge, as new HIV infections among adolescents and young people have not decreased fast enough to curb the epidemic. The combination of slow HIV response and increasing youth populations 15-24 could affect progress towards 2030 goals. : This analysis aimed to describe global and regional trends from 2010-2050 in the HIV epidemic among adolescents and young people by accounting for demographic projections and recent trends in HIV interventions. : 148 national HIV estimates files were used to project the HIV epidemic to 2050. Numbers of people living with HIV and new HIV infections were projected by sex and five-year age group. Along with demographic data, projections were based on three key assumptions: future trends in HIV incidence, antiretroviral treatment coverage, and coverage of antiretrovirals for prevention of mother-to-child transmission. Results represent nine geographic regions. : While the number of adolescents and young people is projected to increase by 10% from 2010-2050, those living with HIV is projected to decrease by 61%. In Eastern and Southern Africa, which hosts the largest HIV epidemic, new HIV infections among adolescents and young people are projected to decline by 84% from 2010-2050. In West and Central Africa, which hosts the second-largest HIV epidemic, new infections are projected to decline by 35%. : While adolescents and young people living with HIV are living longer and ageing into adulthood, if current trends continue, the number of new HIV infections is not projected to decline fast enough to end AIDS as a health threat in this age group. Regional variations suggest that while progress in Eastern and Southern Africa could reduce the size of the epidemic by 2050, other regions exhibit slower rates of decline among adolescents and young people.