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Pregnant Women Pass on COVID Vaccine Protection to Newborns

THURSDAY, March 25, 2021 -- In some good news to emerge from the coronavirus pandemic, new research shows that pregnant women and new breastfeeding moms have a strong immune response to COVID-19 vaccines and can transfer that immunity to their infants.

The study included 131 women of reproductive age (84 pregnant, 31 lactating and 16 not pregnant) who received one of two mRNA vaccines: Pfizer or Moderna.

Vaccine-induced antibody levels were similar in all three groups of women, and antibody levels triggered by vaccination were much higher than levels induced by natural infection with COVID-19 in pregnancy, the researchers said.

They also found that vaccine-generated antibodies were present in all umbilical cord blood and breast milk samples taken from women in the study, showing that the antibodies are passed from mothers to their infants.

The study, the largest of its kind to date, was published March 25 in the American Journal of Obstetrics and Gynecology.

"This news of excellent vaccine efficacy is very encouraging for pregnant and breastfeeding women who were left out of the initial COVID-19 vaccine trials," said study co-senior author Dr. Andrea Edlow, a maternal-fetal medicine specialist at Massachusetts General Hospital (MGH).

"Filling in the information gaps with real data is key -- especially for our pregnant patients who are at greater risk for complications from COVID-19," Edlow said in a hospital news release.

"We now have clear evidence the COVID vaccines can induce immunity that will protect infants," said co-senior author Galit Alter, from the Ragon Institute at MGH.

"We hope this study will catalyze vaccine developers to recognize the importance of studying pregnant and lactating individuals, and include them in trials," Alter said in the release. "The potential for rational vaccine design to drive improved outcomes for mothers and infants is limitless, but developers must realize that pregnancy is a distinct immunological state, where two lives can be saved simultaneously with a powerful vaccine."

The researchers also found that levels of mucosal (IgA) antibodies were higher after the second dose of Moderna compared to the second dose of Pfizer.

"This finding is important for all individuals, since SARS-CoV-2 is acquired through mucosal surfaces like the nose, mouth and eyes," said co-author Dr. Kathryn Gray, an obstetrician at Brigham and Women's Hospital in Boston. "But it also holds special importance for pregnant and lactating women because IgA is a key antibody present in breast milk."

© 2021 HealthDay. All rights reserved.

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