Both the Pfizer and Moderna COVID-19 vaccines are effective in pregnant and lactating women, who can then pass along protective antibodies to their newborns, according to research published in the American Journal of Obstetrics and Gynecology.
The study looked at antibody levels of 131 women who received either vaccine between mid-December and late-February. Of those participants, 84 were pregnant, 31 were lactating and 16 women were not pregnant or lactating. Both the mother’s blood and breastmilk, if applicable, were tested for antibodies.
Vaccinated pregnant and lactating women showed higher levels of antibodies when compared to samples taken from non-vaccinated pregnant women who contracted COVID-19 and recovered.
Researchers also found that vaccine-generated antibodies were present in umbilical cord blood and breastmilk samples, indicating they can be transferred to newborns.
“We now have clear evidence the COVID vaccines can induce immunity that will protect infants,” said Galit Alter, PhD, core member of the Ragon Institute and co-senior author of the study.
The researchers were also able to look at any potential differences between antibodies levels after the Pfizer vaccine compared to the Moderna one.
They found levels of antibodies in the nose, mouth and eyes, called IgA, were higher after the second dose of the Moderna COVID-19 vaccine compared to after the second dose of the Pfizer vaccine.
“This finding is important for all individuals, since SARS-CoV-2 is acquired through mucosal surfaces like the nose, mouth and eyes,” said Kathryn Gray, MD, PhD, an obstetrician at Brigham and Women’s Hospital and a first author of the paper. “But it also holds special importance for pregnant and lactating women because IgA is a key antibody present in breastmilk.”
Researchers say more study is needed to determine how long those protective antibodies last in newborns.