Chapter 58: HIV Infection

INTRODUCTION

Perinatal transmission is the most common route of human immunodeficiency virus type 1 (HIV-1) infection among infants and children.¹ Since the first reports of pediatric acquired immune deficiency syndrome (AIDS) cases more than 3 decades ago,² extraordinary advances have occurred in the prevention and treatment of pediatric HIV infection.^{3, 4, 5, 6, 7, 8, and 9} The epidemiology of the perinatal HIV epidemic has dramatically changed in the United States and other resource-rich countries because of effective implementation of strategies to prevent vertical transmission.^{7, 8, and 9} Improved survival of HIV-infected children into adolescence and adulthood because of the availability of highly active antiretroviral therapy (HAART) has significantly improved the health and longevity of HIV-infected children.^{3, 4, 5, and 6}

Preventing perinatal HIV transmission became a reality in 1994 when the Pediatric AIDS Clinical Trials Group (PACTG) 076 published data showing that a long complex course of zidovudine (ZDV) prophylaxis given to an HIV-1-infected mother during early gestation and labor and then postnatally to the baby reduced perinatal HIV-1 transmission by almost two-thirds.¹⁰ In 1995, the US Public Health Service (USPHS) issued guidelines recommending universal counseling and testing for pregnant women and use of ZDV to reduce perinatal transmission.¹¹ Since then, rates of perinatal HIV transmission in the United States and Europe have decreased to less than 1%–2% because of widespread implementation of universal antenatal HIV testing, combination antiretroviral treatment (ART) during pregnancy, elective cesarean section, and avoidance of breast-feeding through the use of formula milk.^{1, 12, 13, and 14} Currently, new pediatric HIV infections are rare in the United States and occur primarily because of missed prevention opportunities.¹⁵ In recent years, remarkable progress has occurred in the prevention of mother-to-child HIV transmission (PMTCT) during breast-feeding.^{16, 17, and 18} However, translation of research into policy and practice remains a major challenge in many low- and middle-income countries (LMIC).^{16, 17, 18, 19, and 20}

This chapter reviews the epidemiology of perinatal HIV infection; discusses the pathophysiology of transmission; reviews the diagnosis, differential diagnosis, and clinical manifestations; describes the treatment and outcomes; and briefly summarizes the current perinatal HIV preventive strategies focusing primarily in the United States. Review of the global advances in PMTCT is outside the scope of this chapter, and they are not discussed; excellent reviews have been published on this topic.^{1, 8, 16, 17, and 18}

EPIDEMIOLOGY

Global Scope of the Problem

The World Health Organization (WHO) progress report in 2011 estimated that 34 million (31.6–35.2 million) adults worldwide were living with HIV/AIDS.²⁰ Approximately 2.7 million (2.4–2.9 million) adults had become newly infected with HIV in 2010 and 1.8 million (1.6–1.9 million) HIV-infected individuals ...