Evaluation and antiretroviral (ARV) prophylaxis of HIV-exposed infants.
Review routes of HIV transmission; evaluation of HIV-exposed infants; recommendations for infant ARV prophylaxis
Mother-to-child transmission (MTCT) of HIV can occur during pregnancy (intrapartum), at the time of birth (perinatal), or through breastfeeding (postpartum). The risk of MTCT of HIV can be reduced from 25–30% to <1% with maternal combination ARV therapy during pregnancy, infant ARV prophylaxis, and avoidance of breastfeeding. Risk factors for perinatal HIV transmission include high maternal viral load, low maternal CD4 count, chorioamnionitis, other sexually transmitted infections, and vaginal delivery. Most infants with HIV infection are asymptomatic at birth, but approximately 25% of these infants progress rapidly to AIDS and death. Early diagnosis and treatment reduces mortality by at least 75% among HIV-infected infants.
Strict avoidance of breastfeeding is recommended for all HIV-exposed infants in the United States. A blood HIV DNA polymerase chain reaction (PCR) or qualitative HIV RNA PCR should be drawn from all HIV-exposed newborns after a brief bath is performed (do not delay starting infant ARV prophylaxis). In addition, HIV DNA PCR or qualitative HIV RNA PCR should be performed at ages 2 weeks, 1–2 months, and 4 months. For very high-risk infants, virologic testing could also be considered at 6 months of age. Infants with positive virologic testing should have immediate confirmatory testing (repeat DNA PCR or qualitative HIV RNA PCR on a new blood specimen) and evaluation by a pediatric infectious diseases specialist for consideration of combination ARV therapy. The ARV regimen for infant prophylaxis is determined based on an assessment of the risk of MTCT.
For low-risk infants born to HIV-infected mothers on combination ARV therapy with undetectable HIV viral loads during pregnancy, a 4–6-week course of zidovudine (AZT) (term infants: 4 mg/kg by mouth twice daily) is recommended (with first dose given as soon as possible after birth).
For high-risk infants born to HIV-infected mothers with a detectable viral load near delivery or who were not on combination ARV therapy prior to delivery, two-drug ARV prophylaxis is recommended. In addition to a 6-week course of AZT, three doses of nevirapine (NVP) (birth weight >2 kg: 12 mg per dose by mouth) should be given. The first dose is administered as soon as possible after birth, the second dose is given 48 hours after the first dose, and the third dose is given 96 hours after the second dose.
For very high-risk infants (e.g., mother had a high HIV viral load prior to delivery or has suspected or known ARV-resistant virus), a three-drug ARV prophylaxis regimen should be considered in consultation with a pediatric infectious disease specialist.
Figure 44.1 presents an algorithm for risk stratification and ARV prophylaxis of HIV-exposed infants.
Algorithm for risk stratification and ARV prophylaxis of HIV-exposed infants. ARV, antiretroviral; AZT, zidovudine; ID, infectious diseases; NVP, nevirapine; VL, viral load.