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Getting Vaccinated During Pregnancy Cuts Baby’s COVID-19 Risk, Study Says

4 minute read

COVID-19 vaccination during pregnancy provides strong protection for both mother and baby, new data from the U.S. Centers for Disease Control and Prevention (CDC) suggest.

Babies born to mothers who received two mRNA vaccine doses during pregnancy were 61% less likely to be hospitalized with COVID-19 in their first six months of life, compared to babies born to women who were not vaccinated during pregnancy, according to the CDC’s new report. The shots were effective whenever expectant mothers were vaccinated, but offered even more protection when given 21 weeks into the pregnancy or later.

The CDC recommends COVID-19 vaccination for pregnant people, since they are at high risk for complications if they get infected during pregnancy. Vaccination is safe and effective for mother and baby, the agency says. In November, the American College of Obstetricians and Gynecologists also recommended boosters for all eligible pregnant people.

The new study, published Feb. 15 in the CDC’s Morbidity and Mortality Weekly Report, offers the first real-world evidence that vaccination during pregnancy can also help keep infants safe from the virus. Disease-fighting antibodies generated by vaccination seem to pass from mother to baby in utero and offer protection against severe disease and hospitalization, the study’s authors write.

“Today’s news is highly welcome, particularly in the backdrop of the recent increase in hospitalizations among very young children,” said Dr. Dana Meaney-Delman, chief of the CDC’s Infant Outcomes Monitoring Research and Prevention Branch, during a press briefing. “Unfortunately, vaccination of infants younger than six months old is not currently on the horizon, highlighting why vaccination during pregnancy is so important.”

The CDC’s study was fairly small; researchers examined data from almost 400 infants younger than 6 months who were hospitalized across 17 states from July 2021 to January 2022. Roughly half of those infants were hospitalized with COVID-19. The other babies were hospitalized for other causes and served as a control group. Across both groups, the median age was two months. About 20% of the babies had at least one underlying medical condition, and about 20% were born premature.

Among the infants hospitalized for COVID-19, 84% were born to mothers who were not vaccinated during pregnancy, the CDC found.

Babies born to mothers who were vaccinated during pregnancy were 61% less likely to be hospitalized with COVID-19 than babies born to unvaccinated mothers. The timing of the vaccination seemed to matter, as well. Babies born to mothers who were vaccinated at least 21 weeks into their pregnancies were 80% less likely to be hospitalized with COVID-19 than those with unvaccinated moms; that number dropped to 32% for babies born to mothers who got their shots in the first 20 weeks.

Nonetheless, the CDC has not recommended vaccination at any specific point in pregnancy. While getting vaccinated later in a pregnancy might confer more protection to the baby, pregnant people are susceptible to severe disease and pregnancy complications if they do get infected, which also makes it important to be protected as early as possible, Meaney-Delman said during the press briefing.

Vaccination rates among pregnant people have lagged behind those of the general U.S. population. That’s likely a holdover from the early days of vaccine rollout, when little was known about how the shots affected pregnant people and fetuses. Vaccination rates have risen in recent months, following the release of strong data on the shots’ safety and efficacy, but “we still have a lot of work to do,” Meaney-Delman said

The new data may help persuade expectant moms. Since children under five are not eligible to be vaccinated against COVID-19, the report offers reassuring data to new and expectant parents during an otherwise frustrating time.

A U.S. Food and Drug Administration expert committee was scheduled to meet on Feb. 15 to discuss expanding authorization of Pfizer-BioNTech’s vaccine to children ages 6 months to 4 years, but that meeting was postponed while Pfizer gathers more data from its ongoing clinical trial. That means babies and toddlers may not be vaccinated for months to come.

However, as the new data show, parents-to-be do have a way to protect their newborns and themselves: getting vaccinated during pregnancy.

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Write to Jamie Ducharme at jamie.ducharme@time.com