COVID-19 Vaccination in Pregnancy Passes Antibodies to Newborns

There is good news for pregnant and lactating women regarding COVID-19 vaccines.

Several recent studies indicate COVID-19 vaccines are highly effective in safely creating antibodies in pregnant women. Moreover, vaccinated mothers can pass along protective immunity to newborns through breast milk and the placenta.

The studies shed light on a question that had left many pregnant women in a quandary over whether to get the vaccine. Pregnant and breastfeeding women were left out of the initial COVID-19 vaccine trials.

This research is encouraging for pregnant women who want to protect both themselves and their newborns against COVID-19.

According to the Centers for Disease Control and Prevention, pregnant women who become infected with COVID-19 are more likely to become severely ill and are at increased risk for adverse pregnancy outcomes. This makes the news about the vaccine’s efficacy for pregnant women all the more important. And, it should reassure moms-to-be who have chosen to get vaccinated.

The recent studies indicate vaccines triggered antibody production in pregnant women as soon as five days after the first dose and the transfer of antibodies across the placenta to the baby appears to begin as soon as 16 days after the first dose.

All of this suggests that pregnant women should not delay getting fully vaccinated against COVID-19.

In one of the largest studies of its kind, published recently in the American Journal of Obstetrics & Gynecology, researchers evaluated 84 pregnant women, 31 lactating women and 16 women who were not pregnant. All of them had received either the Pfizer or Moderna vaccines. The antibody levels in blood were the same in all three groups and side effects were rare and comparable among all the women.

Antibodies from the vaccine were detected in umbilical cord blood and breast milk samples taken during the study, indicating a transmission of antibodies from mothers to their newborns.

The study involved patients and researchers at Brigham and Women's Hospital, Massachusetts General Hospital and the Ragon Institute.

While it’s clear that vaccinated mothers can pass along COVID-19 antibodies to their children, what’s less certain is how these antibodies protect the infant from the virus.

Research is a bit murky and too early to assume that babies of vaccinated mothers who breastfeed can’t get infected with the virus, but the evidence suggests that could be the case.

Nonetheless, the research showing that pregnant women show a robust immune response to vaccines and pass those antibodies onto their newborns is another bit of positive news in the war against the virus.