Infants face high hospitalization risk
Babies under 6 months old continue to experience some of the highest COVID-19 hospitalization rates of any age group, yet no vaccine is approved for them. That vulnerability has led the American College of Obstetricians and Gynecologists (ACOG) to recommend COVID vaccination during pregnancy.
“There are a number of studies that show one of the benefits of COVID vaccination during pregnancy is the passage of antibodies to the newborn,” said Dr. Kevin Ault, professor of obstetrics and gynecology at Western Michigan University. “That protects the newborn against COVID.”
Large study reinforces guidance
A new study published in Pediatrics followed 146,031 children born in Norway between March 2020 and December 2023. About one in four of their mothers received a COVID vaccine during pregnancy.
The findings show that infants exposed to vaccination in utero were about 50% less likely to require hospital care for COVID during their first two months of life compared with infants whose mothers were not vaccinated. Between 3 and 5 months of age, the risk was 24% lower among vaccine-exposed infants. The protective effect diminished after 6 months.
Importantly, researchers found no increased risk of other infections in babies whose mothers were vaccinated. “COVID vaccination in pregnancy protected the infant against COVID and had no apparent effect on other infections,” said lead author Dr. Helena Niemi Eide of the University of Oslo.
No evidence of broader infection risk
The study addressed claims that vaccination during pregnancy could lead to immune problems in infants. Babies whose mothers received the vaccine were no more likely to be hospitalized for infections overall. Although they were slightly more likely to have primary care visits for infections, researchers attributed this to differences in health-seeking behavior rather than biological effects.
“If you’re more likely to get vaccinated during pregnancy, you’re probably more likely to take your newborn to the doctor,” Ault said, noting there is no biological mechanism suggesting increased infection risk.
Context amid shifting policy debates
Previous research has shown that pregnancy increases the risk of severe COVID illness, including hospitalization and ventilator use. U.S. data indicate that hospitalization rates for infants under 6 months can rival those of adults aged 65 to 74, with about one in five hospitalized infants requiring intensive care.
The Norwegian study was funded by academic and government institutions without pharmaceutical industry support. Pediatrician Dr. Thomas Nguyen said the large dataset provides reassurance about earlier clinical recommendations. “This study confirms that vaccination during pregnancy protects young infants before they’re old enough to be vaccinated themselves,” he said.
While policy discussions continue at the federal level, the new data add to growing evidence that maternal COVID vaccination offers measurable early-life protection without increasing other infection risks.