1. George K. Siberry, MD, MPH* 1. *Maternal and Pediatric Infectious Disease Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD * Abbreviations: ART: : antiretroviral therapy ARV: : antiretroviral cART: : combination antiretroviral therapy CDC: : Centers for Disease Control and Prevention EIA: : enzyme-linked immunoassay HIV: : human immunodeficiency virus MAC: : Mycobacterium avium complex MMR: : measles-mumps-rubella MSM: : men who have sex with men MTCT: : maternal-to-child transmission OI: : opportunistic infection PCP: : Pneumocystis pneumonia PCR: : polymerase chain reaction STI: : sexually transmitted infection Effective prevention strategies have reduced the risk of perinatal transmission of human immunodeficiency virus (HIV) infection to less than 1% to 2% in the United States, but failures to fully implement these strategies result in continued preventable infant HIV infections. In addition, the increasing number of sexually acquired HIV infections in adolescents underscores the important role of the pediatrician in preventing and diagnosing HIV infection in youth. After completing this article, readers should be able to: 1. Recognize the important role that the pediatrician plays in the prevention, detection, and care of patients infected with and affected by human immunodeficiency virus (HIV). 2. Understand the epidemiology of HIV infection in infants, children, and adolescents. 3. Select the proper HIV diagnostic testing plan for infants, children, and adolescents. 4. Plan the comprehensive management of HIV-exposed infants. 5. Recognize the clinical conditions suggestive of HIV infection, including the major opportunistic infections seen in patients with HIV/AIDS. 6. Understand the principles, monitoring, and complications of HIV treatment in infants, children, and adolescents. Since the first description of infants with human immunodeficiency virus (HIV) infection in the early 1980s, (1)(2) tremendous advances have been made in the understanding, prevention, and treatment of HIV infection. Effective prevention strategies have reduced the risk of perinatal transmission, or maternal-to-child transmission (MTCT), of HIV infection to less than 1% to 2% in the United States, and the World Health Organization has made global elimination of new infant HIV infections a realistic target by 2015. (3) For those children who have HIV infection, the development of potent antiretroviral (ARV) drugs has transformed a once progressive and often fatal infection for children into a chronic condition …