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Study shows two vaccine doses for mothers eases COVID complications for infants

Jul. 6, 2022, 2:57 PM


by Jessica Pasley

Infants younger than 6 months were better protected from COVID-19 complications when mothers received two doses of the vaccine while pregnant, according to researchers.

Mothers who received COVID-19 vaccinations during pregnancy reduced the risk of hospitalization for this age group by 80% during the delta wave and nearly 40% during the omicron wave, according to a recent New England Journal of Medicine study led by Natasha Halasa, MD, MPH, first author on the paper and Craig Weaver Professor of Pediatrics at Monroe Carell Jr. Children’s Hospital at Vanderbilt.

“This study reinforces the importance of COVID-19 vaccination during pregnancy to protect both pregnant people and their babies from COVID-19,” said Halasa. “The study provides real-world evidence that protection offered by COVID-19 vaccination during pregnancy extends beyond the pregnant person to also help protect their baby from getting very sick and needing to be hospitalized from COVID-19.”

The study looked at the effectiveness of maternal COVID-19 vaccination to protect against infant hospitalization by variant as well as by timing of vaccination during pregnancy. It also further supports recommendations for COVID-19 vaccination during pregnancy.

The study analyzed data from 1,049 infants (537 infants with COVID-19 and 512 controls) from 30 hospitals across 22 states in the CDC-funded Overcoming COVID-19 Network between July 1, 2021, and March 8, 2022.

Key findings:

  • Ninety percent of infants who required hospitalization in intensive care units due to COVID-19 infection were born to mothers who were not vaccinated during pregnancy.
  • Effectiveness of maternal COVID-19 vaccination to prevent hospitalization in babies younger than 6 months was higher among mothers fully vaccinated after 20 weeks.
  • Maternal vaccination has dual benefits including protecting mothers and providing additional protection to their babies.

“COVID-19 vaccination during pregnancy leads to the presence of detectable maternal antibodies in cord blood, breast milk, and serum specimens obtained from infants, findings that indicate the transfer of maternal antibodies to infants; antibody titers among infants are highest when maternal vaccination occurs late in the second trimester or early in the third trimester of pregnancy,” reads the study.

Halasa said that further studies are needed to determine the optimal timing of COVID-19 vaccination, including booster doses, during pregnancy.

“We hope these study results encourage pregnant women to get vaccinated, not only to protect themselves, but their infants.”

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