Vaccines for COVID-19 are being administered to millions of people across the world.

A new study by Gray K.J. et al. (March 25, 2021) published in American Journal of Obstetrics and Gynecology found the mRNA COVID-19 vaccines can be effective in producing antibodies against the SARS-CoV-2 virus in pregnant and lactating women.

The study found protective vaccine-generated antibodies were found in umbilical cord blood and breast milk after maternal vaccination.

The study compared vaccinated pregnant and lactating women with non-pregnant women, and with naturally infected pregnant women.

This new study provides the first data from a large cohort (131 women) on maternal antibody generation in response to COVID-19 vaccination (Pfizer/BioNTech and Moderna).

The study suggests vaccination of pregnant and lactating women can "confer robust maternal and neonatal immunity."

The study:

  • Researchers at Massachusetts General Hospital, Brigham and Women's Hospital and the Ragon Institute of MGH, MIT and Harvard looked at 131 women.
  • All 131 women were in the reproductive age group and they were enrolled in two academic medical centres.
  • Of the 131 women; 84 were pregnant, 31 were lactating, and 16 were non-pregnant.
  • The vaccinated women received either the Pfizer/BioNTech or Moderna mRNA vaccines.
  • For the pregnant women, the average time of the first vaccine dose was 23 weeks.
  • Of the three trimesters: around 13% were vaccinated in the first, 46% in the second, 40% in the third.

  • Samples were collected between December 17, 2020 and March 2, 2021.

The key findings:

To quote from the published paper:

"COVID-19 mRNA vaccines generated robust humoral immunity in pregnant and lactating women, with immunogenicity and reactogenicity similar to that observed in non-pregnant women."

Vaccine-induced immune responses were significantly greater than the response to natural infection. Immune transfer to neonates occurred via placenta and breastmilk."

What does this mean?

According to this easy-to-understand article in CTVNEWS: "The vaccine-induced antibody levels were equivalent in pregnant and lactating women, compared to non-pregnant women. The antibody levels were "strikingly higher" than those resulting from coronavirus infection during pregnancy"

In summary, according to the Gray et al paper:

"This study provides the first data from a large cohort on maternal antibody generation in response to COVID-19 vaccination, compares vaccine-generated immunity to that from natural infection in pregnancy, and suggests vaccination of pregnant and lactating women can confer robust maternal and neonatal immunity."


Article and science reference:

Easy to understand CTVNEWS article about the research:

Easy-to-understand article in ScienceDaily:

Easy to read article NEWS-MEDICAL article explaining the research (based on the pre-print):


Science reference:

Gray, K. J. et al. (2021). COVID-19 vaccine response in pregnant and lactating women: a cohort study. American Journal of Obstetrics and Gynecology, March 25th 2021


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