Two studies released this month found evidence that COVID-19 vaccination of mothers during pregnancy can provide levels of protection to their babies to help avoid severe outcomes from COVID-19.

The studies, one from the Centers for Disease Control and Prevention (CDC) published Friday and one from Massachusetts General Hospital (MGH) published Feb. 7, found respectively that vaccination during pregnancy helps to prevent hospitalization for COVID-19 in infants and that babies born to vaccinated mothers had higher levels of antibodies than babies born to unvaccinated mothers who were infected with COVID-19.

The MGH study, published in The Journal of the American Medical Association (JAMA), showed 98% of infants in the study whose mothers had been vaccinated had detectable levels of the protective Immunoglobulin G (IgG) at two months after birth.

At six months, the researchers looked at a smaller group — 28 infants with vaccinated mothers and 12 with unvaccinated, infected mothers—and found 57% (16 of 28) of the infants with vaccinated mothers still had detectable IgG, compared with 8% (1 of 12) born to infected mothers.

The CDC study found that during the period from July 2021–January 2022, when the delta and omicron variants of COVID-19 were surging, maternal completion of a two-dose COVID-19 vaccination series during pregnancy was associated with reduced risk for COVID-19 hospitalization among infants younger than six months.

Among 176 infants who were hospitalized with COVID-19, 148 of the infants (84%) were born to mothers who were not vaccinated during pregnancy. Of the 43 infants in the study who were admitted to an ICU, 88% of them had mothers who were unvaccinated.

“CDC recommends that women who are pregnant, are breastfeeding, are trying to get pregnant now, or might become pregnant in the future get vaccinated and stay up to date with COVID-19 vaccination,” the study said.

Dr. Yasaswi Kislovskiy, an OB-GYN and reproductive infectious disease specialist at Allegheny Health Network, said the studies can help answer a number of questions, especially for parents who are wondering whether they still should get vaccinated if they already previously were infected with COVID.

“The really exciting thing about the CDC data is (the study) found it definitely is better to get the vaccine, and it protects not just you, but also probably protects your baby,” she said. “We know that because for people who got vaccinated during their pregnancy, if their babies got COVID, and if the mom had gotten a vaccine, those babies got less sick. That’s really wonderful to know that a mom getting the vaccine can help the baby.”

Kislovskiy said that the JAMA study helps show to what level vaccination protects a baby.

“It definitely seems like getting the vaccine is going to be better for the mom, and more protective for you and the baby,” she said. “Even if you’ve had COVID-19 before, it’s probably still worth it.”

Getting vaccinated while pregnant is safe, as well as getting boosted, Kislovskiy said.

“There’s no increased risk of stillbirth or miscarriage or anatomic changes from getting the vaccine — it’s safe,” she said. “Knowing that the vaccine is safe will hopefully help people to obtain the vaccine.”

While many vaccines for infectious diseases have been able to be transferred from pregnant mother to child, Kislovskiy said the news from the two studies is encouraging as it provides clearer information when it comes to COVID-19 vaccines specifically.

“It’s really exciting to be able to give people concrete facts about this,” she said.

She added that getting COVID also can be particularly dangerous for anyone who is pregnant and especially anyone who is unvaccinated.

“What we do know is that COVID infection itself does put a pregnant person and a baby at risk,” she said. “(More at risk) for needing to be in a hospital, for needing a breathing tube, or for having a miscarriage, or stillbirth, or having a baby who is really small.”