Newborns whose mothers received a COVID-19 vaccine during pregnancy were significantly less likely to be hospitalised with the virus in their first months of life, according to one of the largest studies of its kind to date.
The research, published in the journal Pediatrics and drawing on data from more than 140,000 infants in Norway, found that babies aged two months and under who had been exposed to the vaccine before birth were nearly half as likely to require hospital treatment for COVID-19. Among infants aged three to five months, the likelihood of hospitalisation was reduced by 24 per cent. The protective effect was found to diminish once babies reached six months of age.
The findings carry particular weight given that infants under six months old are currently ineligible for COVID vaccination themselves, yet remain among the most vulnerable. A separate 2024 study conducted in the United States found that babies in this age group were being admitted to hospital with COVID at the same rate as adults aged between 65 and 74, with one in five requiring intensive care.
The mechanism behind the protection is well established. When a pregnant woman receives the vaccine, antibodies are transferred to the baby, offering immunity in the critical early months of life before the child is old enough to be vaccinated directly.
The Norwegian study also addressed a concern that has circulated among vaccine sceptics — the claim that COVID vaccination suppresses the immune system, leaving recipients more vulnerable to other illnesses. The research found no increased risk of other infections among babies born to vaccinated mothers, and no rise in hospital visits unrelated to COVID.
Dr Thomas Nguyen, a paediatrician and associate professor at Ohio University’s Heritage College of Osteopathic Medicine, told NPR that the results directly counter that narrative. “It refutes the whole idea of that being a problem,” he said, noting that any immune suppression effect would have produced measurably higher rates of other infections in the study group — which it did not.
Dr Nguyen also reflected on the early pandemic period, when guidance recommending vaccination for pregnant women was issued with comparatively limited data available. The American College of Obstetricians and Gynecologists had called for pregnant women to be vaccinated after evidence emerged that they faced a higher risk of severe illness and hospitalisation from COVID-19.
“This study basically confirms that we were correct in making those recommendations,” Dr Nguyen said. “It’s good to see our expectations were met with respect to COVID vaccines protecting young infants before they were old enough to get vaccinated themselves.”
The coronavirus has killed more than 7.1 million people worldwide since it was first reported in early 2020. The World Health Organisation estimates that close to 43,000 new cases are still being recorded each month globally, with new variants continuing to emerge.
