Mercy Shibemba, an award-winning activist and advocate for children and young people living with HIV, shares data from the Population-based HIV Impact Assessment (PHIA) surveys in Zimbabwe, Malawi, Zambia, Eswatini, and Lesotho which indicates that high rates of undiagnosed HIV were found among adolescents (ages 10-19 years) in these countries. A study of this analysis, led by ICAP’s Andrea Low, MD, PhD, suggests that a major expansion of testing opportunities, support with treatment, and optimized treatment is critical to address these cases.