COVID-19 vaccine in pregnancy may protect babies after birth

A woman holds a baby in a pink cap while another woman, left, examines the child. All three are wearing masks
In Mexico City, Violet Juarez is held by her mother during an outing with her grandmother. COVID-19 shots during pregnancy may protect babies after their born and lead to fewer infants needing hospitalization, new research suggests.
(Liliana Nieto del Rio / For The Times)

COVID-19 vaccines during pregnancy can protect babies after they’re born and lead to fewer hospitalized infants, a new study suggests.

The report is the first to show potential benefits to infants born to people who received two doses of either the Pfizer-BioNTech or Moderna vaccines during pregnancy, researchers from the Centers for Disease Control and Prevention said during a briefing.

It was already known that antibodies induced in response to COVID-19 vaccines transfer to the fetus through the umbilical cord, but how that might affect infants after birth was uncertain.


“Until this study, we have not yet had data to demonstrate whether these antibodies might provide protection for the baby against COVID-19,” said Dr. Dana Meaney-Delman, an obstetrician and CDC researcher.

Infants in the study were treated at 20 hospitals in 17 states from July 2021 through mid-January, during surges driven by the Delta and Omicron variants of the coronavirus.

The researchers didn’t examine infection rates in infants. Instead, they looked at data on 176 children younger than 6 months who were hospitalized with COVID-19 and compared them with 203 others in the hospital for some other condition. They also looked at the vaccination status of all the babies’ mothers.

Vaccination rates were much lower among mothers of the COVID-19 infants than among those whose infants were hospitalized with something else — 16% compared with 32%. The findings were published Tuesday in the CDC’s Morbidity and Mortality Weekly Report.

The results offer yet another reason for pregnant people to get vaccinated, the researchers said.

A long-standing tradition of keeping pregnant women out of clinical trials is having serious consequences with regard to COVID-19.

About two-thirds of pregnant people in the United States are fully vaccinated; most got the shots before pregnancy, CDC data show.

Other shots given during pregnancy, including vaccines for flu and whooping cough, are known to protect mothers and infants.

The study provides “another important piece of the puzzle,” said Dr. Denise Jamieson, chair of the Department of Gynecology and Obstetrics at Emory University.

She called the results important news for babies who are too young to receive COVID-19 vaccinations. Although shots are being studied for older infants and toddlers, none are on the horizon for infants younger than 6 months.

“It’s not surprising, but very reassuring,” Jamieson said.