Postnatal Antiretroviral Prophylaxis and Perinatal HIV Infection in Medicaid-Enrolled Infants.

Background: Advances in preventive strategies have reduced mother-to-child transmission of HIV. The US Department of Health and Human Services (HHS) guidelines on postnatal antiretroviral prophylaxis have evolved to reflect increasingly available evidence. We sought to provide data on postnatal prophylaxis in clinical practice.

Methods: We performed a retrospective study using the MarketScan Multi-State Medicaid Database (2009-2021). We identified antiretroviral use among infants and classified them into single-, double-, and triple-drug prophylactic, and therapeutic use. We also characterized new HIV infections in infants in terms of demographics and prophylaxis regimen.

Results: Among 3 147 318 infants included in the study, 2304 received postnatal prophylaxis, with 2123 receiving zidovudine alone. Although zidovudine monotherapy was the only prophylaxis used in 2009, the rate dropped to 71.7% by 2021 as combination prophylaxis became increasingly common (P for trend <.001). Triple-drug prophylaxis became more common than double-drug prophylaxis by 2018. Among 52 infants with HIV infection, 27 (51.9%) were diagnosed between 6 weeks and 1 year of life but had not received postnatal prophylaxis, a majority of which were Black (73.8%).

Conclusions: Trends in postnatal HIV prophylaxis in clinical practice closely paralleled evolving HHS recommendations. Although the perinatal HIV infection rate was low, more than half of HIV infections by 1 year of life occurred in infants who had not received postnatal HIV prophylaxis, suggesting missed maternal infections, most frequently among Black individuals. Heightened awareness is essential for identifying HIV infection as early in pregnancy as possible to enable timely treatment and prevention.