What you need to know

Infants less than 6 months of age are too young to receive a COVID-19 vaccine, but they are more likely to require hospitalization and intensive care from SARS-CoV-2 infection than children age 1 to 4 years old. Development of methods to protect these infants from severe COVID-19 is needed.

In a small study supported by the National Institute of Allergy and Infectious Diseases, researchers have found that pregnant and lactating women who were vaccinated and received a booster COVID-19 dose generated antibodies against SARS-CoV-2. The researchers wanted to see whether these antibodies could be transferred to the women’s children.

What did the researchers do?

Between October 2021 and April 2022, researchers collected paired breastmilk and blood samples from 45 lactating women before and after the women had received a booster dose of a COVID-19 vaccine. The researchers also collected blood samples from the women’s children. The milk and blood samples were collected less than 30 days before a booster and again 14 to 35 days after a booster.

The researchers found that the women had higher levels of protective antibodies in their breast milk after being boosted compared with their pre-booster levels, but their children did not have higher levels of blood antibodies. However, the researchers did find protective antibodies in nearly 75% of infants born to women who had been vaccinated during pregnancy. On average, these antibodies from pregnant women were still present when the infants were 5 months old.

Why is this research important?

This study provides more evidence that vaccination among pregnant and lactating women may protect their infants from COVID-19 during the first months of life, when babies are particularly vulnerable. COVID-19 vaccines are safe and effective for pregnant and lactating people, and the Centers for Disease Control and Prevention (CDC) recommends that all people age 6 months and older stay up to date on their COVID-19 vaccinations.

Where can I go to learn more?

COVID-19 Vaccination During Pregnancy Likely Benefits Moms and Babies

• An earlier study reported on the safety of vaccines and the antibody response among pregnant and lactating women.

COVID-19 Vaccines While Pregnant or Breastfeeding

• CDC shares information related to COVID-19 vaccination for pregnant and lactating people.

Booster Vaccine Targeting Omicron Offers Broader COVID-19 Protection

• Targeted COVID-19 booster vaccines create a better immune response than vaccines targeting the original strain of SARS-CoV-2.

Sources

Rick, A. M., Lentscher, A., Xu, L., Wilkins, M. S., Nasser, A., Tuttle, D. J., Megli, C., Marques, E. T. A., McElroy, A. K., Williams, J. V., & Martin, J. M. (2023). Impact of maternal SARS-CoV-2 booster vaccination on blood and breastmilk antibodies. PLOS One, 18(6), e0287103. https://doi.org/10.1371/journal.pone.0287103