Will Getting the COVID Vaccine While Pregnant Give Immunity to Baby?

Pregnant woman receiving the covid-19 vaccine

Getty Images

Key Takeaways

  • A baby has been born in South Florida with COVID-19 antibodies after her mother got the vaccine in her third trimester of pregnancy.
  • The antibodies were present in samples taken from the newborn's umbilical cord blood.
  • Doctors hope the antibodies will help to protect the baby against SARS-CoV-2, the virus that causes COVID-19. 
  • More research is needed to determine how long the protection might last.

The first confirmed case of a baby born with COVID-19 antibodies has been reported, with the findings presented in a preprint study (meaning it's not yet peer-reviewed) and published in Pediatrics.

Research had already established that pregnant women who were previously infected with COVID-19 can transfer antibodies to their baby in the womb. But the case study shows that the COVID-19 vaccine may also give a baby protection from COVID-19 before it's born.

About the Case Study

The South Florida woman, a frontline healthcare worker, received her first Moderna COVID-19 shot when she was 36 weeks pregnant, and three weeks later she gave birth to a healthy baby girl. COVID-19 antibodies were detected in samples taken from the newborn’s umbilical cord blood, both immediately after birth and before delivery of the placenta.

"To our knowledge, this was the first in the world that was reported of a baby being born with antibodies after a vaccination,” co-author Paul Gilbert, MD, told the West Palm Beach ABC affiliate. "We tested the baby’s cord to see if the antibodies in the mother passed to the baby, which is something we see happen with other vaccines given during pregnancy."

Doctors hope that the antibodies will give the baby some protection against SARS-CoV-2, the virus that causes COVID-19. 

"We have demonstrated that SARS-CoV-2 IgG antibodies are detectable in a newborn's cord blood sample after only a single dose of the Moderna COVID-19 vaccine," wrote Dr. Gilbert and his co-author Chad Rudnick, MD. "Thus, there is potential for protection and infection risk reduction from Sars-CoV-2 with maternal vaccination."

Carl Weiner, MD

The likelihood was high that the COVID-19 vaccine, already found to be safe in non-pregnant women, would be safe for pregnant and breastfeeding mothers and generate protective IgG antibodies that would cross the placenta.

— Carl Weiner, MD

However, the doctors also stressed that more research is needed to establish how safe and effective COVID-19 vaccines are during pregnancy.

“This is one small case in what will be thousands and thousands of babies born to mothers who have been vaccinated over the next several months," Dr. Rudnick told the local station. "Further studies have to determine how long this protection will last. They have to determine at what level of protection or how many antibodies a baby needs to have circulating in order to give them protection."

Another recent preprint study of 131 women (84 pregnant, 31 breastfeeding, and 16 non-pregnant), who all received the Pfizer or Moderna vaccine, was carried out at Massachusetts General Hospital.

The researchers found that maternal vaccine-generated antibodies were detected in the umbilical cord blood of all 10 babies who were delivered during the study period. The immune responses were equally strong in the pregnant and lactating women as in the control group, and antibodies were detected in the placenta and breast milk of every sample taken.  

Protection for Baby

Many other vaccines have been shown to pass antibodies from mother to baby via the placenta. "Vaccines not containing active virus have for decades been safely administered during pregnancy to protect either the mother or newborn, or both (e.g., influenza and whooping cough)," says Carl P. Weiner, MD, MBA, FACOG, professor of obstetrics and gynecology and professor of molecular and integrative physiology at University of Kansas School of Medicine.

Dr. Weiner explains that the vaccine doesn't reach the fetus, but rather causes the pregnant woman to produce protective immunoglobulin G (IgG) antibodies—the most common type—that cross the placenta and circulate in the newborn for several months after delivery. Some vaccines also stimulate the production of protective immunoglobulin A (IgA) antibodies that enter into breast milk and are transferred to the breastfeeding newborn, he adds.

"The likelihood was high that the COVID-19 vaccine, already found to be safe in non-pregnant women, would be safe for pregnant and breastfeeding mothers and generate protective IgG antibodies that would cross the placenta and IgA antibodies that would be excreted into the mother’s milk," Dr. Weiner says.

COVID-19 Vaccine During Pregnancy

Pregnant women were excluded from the initial trials of the three COVID-19 vaccines that are currently available in the US: Pfizer/BioNTech, Moderna, and Johnson & Johnson.

But last month, Pfizer announced that the first large-scale trial of its vaccine on pregnant women was underway and expected to finish by the beginning of 2023. Moderna hasn't yet started trials on pregnant women, but has created a registry to track pregnant women who get its shot.

Thousands of pregnant women have had the COVID-19 vaccine already, despite contradictory and confusing advice. The Centers for Disease Control and Prevention (CDC) advises pregnant and breastfeeding women not to take the vaccine, but allows pregnant women to access it, arguing that balancing the benefits and risks is up to the individual.

However, the American College of Obstetricians and Gynecologists (ACOG) recommends that COVID-19 vaccines should not be withheld from pregnant people and should be offered to people who are lactating.

What This Means For You

If you're pregnant during the pandemic, you're probably feeling overwhelmed, and might have lots of questions about you and your baby's health. Your OB/GYN is there to help you address any concerns.

If you get the COVID-19 vaccine during pregnancy, it may give your baby protection from the virus.

Our knowledge is always evolving, Dr. Weiner says. He points to a recent study suggesting that both the Pfizer/BioNTech and Moderna COVID-19 vaccines are effective for pregnant women and their unborn or breastfed babies.

Published in the American Journal of Obstetrics and Gynecology, it found that the vaccine-induced antibody levels in pregnant and lactating women were equivalent to non-pregnant women, and that breastfeeding women passed protective antibodies to their newborns.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

Was this page helpful?
6 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Gilbert P, Rudnick C. Newborn antibodies to SARS-CoV-2 detected in cord blood after maternal vaccination. Pediatrics. doi:10.1101/2021.02.03.21250579

  2. Kubiak JM, Murphy EA, Yee J, et al. Severe acute respiratory syndrome coronavirus 2 serology levels in pregnant women and their neonatesAm J Obstet Gynecol. 2021;225(1):73.e1-73.e7. doi:10.1016/j.ajog.2021.01.016

  3. Gray K, Bordt EA, Atyeo C. COVID-19 vaccine response in pregnant and lactating women: a cohort study. Obstet Gynecol. doi:10.1101/2021.03.07.21253094

  4. BioNTech. Pfizer and BioNTech commence global clinical trial to evaluate COVID-19 vaccine in pregnant women.

  5. CDC. Information about COVID-19 vaccines for people who are pregnant or breastfeeding.

  6. American College of Obstetricians and Gynecologists. Vaccinating pregnant and lactating patients against COVID-19.