Babies whose mothers get vaccinated against Covid-19 during pregnancy are less likely to be admitted to hospital for the disease after they are born, a study suggests.
The new findings are the first real-world evidence that pregnant women can not only protect themselves by getting vaccinated but can also protect their newborn infants.
Babies of mothers who had two doses of the Moderna or Pfizer/BioNTech vaccines while pregnant had a much lower risk of being hospitalised with Covid-19 in the first six months of their lives, according to the study from the US Centers for Disease Control and Prevention (CDC).
“The data CDC is publishing today provides real-world evidence that getting a Covid-19 vaccine during pregnancy might help protect infants less than six months of age from hospitalisation due to Covid-19,” Dr Dana Meaney-Delman, the CDC’s chief of infant outcomes monitoring research and prevention branch, told a press briefing.
This is likely because they are born carrying their mother’s antibodies, she said.
“When people receive an mRNA Covid-19 vaccine during pregnancy, their bodies build antibodies to protect against Covid-19 and these antibodies have been found in umbilical cord blood, indicating that the antibodies have transferred from the pregnant person to the developing infant. And while we know that these antibodies cross the placenta, until this study, we have not yet had data to demonstrate whether these antibodies might provide protection for the baby against Covid-19.”
Researchers from paediatric hospitals and the CDC looked at children under six months old between July 2021 and January 2022.
The study analysed data from 379 hospitalised babies – 176 with Covid-19 and 203 who were admitted for other issues. It found that Covid-19 vaccines were 61% effective overall at preventing hospitalisations in children whose mothers were vaccinated during pregnancy.
That protection rose to 80% when the mothers were vaccinated after 21 weeks to 14 days before delivery. Vaccination effectiveness fell to 32% for the babies whose mothers were inoculated earlier during their pregnancy. The study did not include data on vaccine effectiveness of booster jabs, or on mothers who were vaccinated before pregnancy.
“The study found that Covid-19 vaccination during pregnancy was 61% protective,” said Meaney-Delman. “Meaning that babies less than six months old, whose mothers were vaccinated, were 61% less like to be hospitalised with Covid-19. And in fact, the majority of babies, actually 84% who were hospitalised with Covid-19, were born to people who were not vaccinated during pregnancy.
“Most concerning, they found that among babies with Covid-19, who were admitted to the ICU, the sickest babies, 88% were born to mothers who were not vaccinated before or during pregnancy. And the one baby who died in the study was born to a mother who was not vaccinated. The bottom line is that maternal vaccination is a really important way to help protect these young infants.”
The study’s authors warned that the estimates for effectiveness earlier in pregnancy should be interpreted with caution due to the small sample size.
Pregnant women are at increased risk for severe illness from Covid-19, and having Covid during pregnancy can increase the risk of preterm birth, stillbirth and possibly other pregnancy complications.
Health experts recommend that women who are pregnant, are breastfeeding, are trying to get pregnant now, or might become pregnant in the future get vaccinated and stay up to date with Covid-19 jabs.