Pregnant Women Get Sub-Par Benefit From First Vaccine Dose

By Reuters Staff

October 28, 2021

(Reuters) - Women who get the first dose of an mRNA COVID-19 vaccine while pregnant or breastfeeding need the second dose to bring their protective benefit up to normal, according to a new study.

Researchers compared immune responses to the mRNA vaccines from Moderna Inc or Pfizer Inc and partner BioNTech SE in 84 pregnant women, 31 breastfeeding women, and 16 similarly-aged nonpregnant, non-lactating women.

After the first shot, everyone developed antibodies against the coronavirus. But antibody levels were lower in women who were pregnant or breastfeeding. Other features of the immune response also lagged in the pregnant and lactating women after the first dose but "caught up" to normal after the second shot.

In a report in Science Translational Medicine, the researchers explained that in order for a mother's body to nurture the fetus, "substantial immunological changes occur throughout pregnancy." The new findings, they added, suggest that pregnancy alters the immune system's response to the vaccine.

Given that pregnant women are highly vulnerable to complications from COVID-19, "there is a critical need" for them to get the second dose on schedule, the researchers said.

SOURCE: https://bit.ly/3vSvWer Science Translational Medicine, online October 19, 2021.

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