Some U.S. newborns still get HIV despite efforts to screen for it. Here’s why

More than half of U.S. newborns diagnosed with HIV in their first year of life had not been given a treatment known to prevent postnatal transmission from mother to child. That suggests that some maternal infections have been missed, researchers report in the July Pediatrics.

“We need to do a better job of identifying HIV in pregnant women,” says Kengo Inagaki, a pediatric infectious diseases physician at the University of Michigan in Ann Arbor.

Pregnant women are usually tested for HIV in the first trimester of pregnancy. A second test is given in the third trimester, but typically only for women at high risk or in states with higher rates of HIV. If a mom-to-be has a positive test, she will begin taking an antiviral viral regimen to reduce HIV in the bloodstream, and if her viral load is still high, she will have a Cesarean section to further reduce the risk of transmission. And, immediately after birth, the babies are given the current HIV antiretroviral therapy — a trio of drugs given orally through a syringe. The therapy reduces transmission risk from 25 percent to less than 1 percent.

But sometimes HIV cases in moms-to-be get missed.

Inagaki and colleagues analyzed Medicaid records of more than 3 million babies born from 2009 to 2021. Of those, 2,304 had been given an HIV prophylaxis after birth. But 52 babies had HIV a year after birth and just over half — 27 — had not been given the prophylaxis, indicating that the mother’s infection had been missed. The other half probably got an earlier, less effective treatment that relied on a single drug instead of the usual three. Black infants were the most likely to be diagnosed with HIV a year later and made up 74 percent of those not given the prophylaxis.

Those numbers are small, but HIV can be devastating and costly to families. And it’s preventable.

The three drug combination has led to a dramatic decline in perinatal HIV from 1,610 in 1990 to fewer than 200 cases annually in the United States in recent years. While women make up only 18 percent of those diagnosed with HIV in the United States, 60 percent are of childbearing age. Several thousand women with HIV give birth annually.

The findings suggest that third trimester maternal HIV testing should be universal rather than risk-based to provide timely treatment and prevention of HIV in children, Inagaki says.