THURSDAY, July 24, 2025 (HealthDay News) -- Although the rate of perinatal HIV infection is low, more than 50 percent of HIV infections in infants before age 1 year occurred in those who did not receive postnatal prophylaxis, according to a study published online June 17 in Pediatrics.Mingyue Lu, from the University of Michigan in Ann Arbor, and colleagues conducted a retrospective study using the MarketScan Multi-State Medicaid Database for 2009 to 2021 to provide data on postnatal HIV prophylaxis. Antiretroviral use was identified among infants and classified into single-, double-, and triple-drug prophylactic and therapeutic use.Overall, 2,304 of the 3,147,318 infants included in the study received postnatal prophylaxis, with 2,123 receiving zidovudine alone. The researchers found that in 2009, zidovudine monotherapy was the only prophylaxis used, but the rate decreased to 71.7 percent by 2021, as the use of combination prophylaxis increased. By 2018, use of triple-drug prophylaxis became more common than double-drug prophylaxis. Overall, 51.9 percent of the 52 infants with HIV infection were diagnosed between 6 weeks and 1 year of life, but had not received postnatal prophylaxis; most of these patients were Black (73.8 percent)."When newborns aren't getting preventive treatment, it suggests we may be missing HIV infections in pregnant women and missing critical opportunities to intervene," senior author Kengo Inagaki, M.D., also from the University of Michigan, said in a statement.Abstract/Full Text (subscription or payment may be required).Sign up for our weekly HealthDay newsletter