Do COVID Vaccines (and Boosters) Protect You During Pregnancy?

May. 17, 2021
A new study examines immune responses of pregnant people


January 5, 2022: Everyone over the age of 12 in the U.S. is now eligible for COVID vaccine boosters, including pregnant people. Learn more about when and how to get a COVID booster from our experts. If you get a COVID primary vaccine series or booster while pregnant or after delivery, you may be eligible to participate in the COVID Vaccine Pregnancy study detailed below.

Sign up to participate.

If you are pregnant or holding a brand new bundle of joy, you probably carried an extra weight of anxiety during this pandemic. Catching COVID is riskier during pregnancy and could cause poor birth outcomes. And COVID vaccines are likely to protect you, but we don’t have solid data on how well they work during pregnancy.

That is why the University of Rochester Medical Center is joining a national clinical trial to study the immune responses of people who get their COVID vaccination during pregnancy or shortly after giving birth.

“The immune system is suppressed during certain stages of pregnancy,” said local study lead Angela Branche, M.D., an associate professor of Infectious Diseases and co-director of the Vaccine and Treatment Evaluation Unit at URMC. “We need to make sure COVID vaccines protect pregnant people as well as they protect everyone else.”

In addition to determining the safety and efficacy of the vaccines during pregnancy, the study will also investigate whether parents can pass COVID protection onto their babies – either in the womb or via breastmilk after they’re born.

Pregnant woman receiving COVID vaccine at a community clinic.
Pregnant woman receiving COVID vaccine at a community clinic.

The trial, which is sponsored by the National Institutes of Health, will enroll 2,000 volunteers who are pregnant or breastfeeding across the U.S. as well as their babies. That will include 135 people from the Rochester area: 100 who were recently vaccinated or plan to be vaccinated while pregnant, and 35 who were or will be vaccinated shortly after giving birth. Study volunteers will not be vaccinated through the trial but should plan to get their COVID vaccinations through community clinics.

Study participants will have up to six study visits and their babies will have up to four visits over the course of one year. Some visits will take place in the clinic, while others may be done at participants’ homes. Blood will be collected several times from the participants - and their babies - and they can elect to donate two or three breast milk samples over the course of the study. For those who were vaccinated during pregnancy, the study team will also collect umbilical cord blood when their child is born.

“In addition to being compensated for participating, moms will also find out if their babies are protected from COVID through the study,” said Courtney Olson-Chen, M.D., assistant professor of Obstetrics and Gynecology at URMC. “After a challenging year, that is one bonus of the trial that will hopefully offer a little peace of mind.”

The URMC study team, which also includes Cynthia M. Rand, M.D., MPH, associate professor of Pediatrics at URMC, will look for protective antibodies in blood and breastmilk samples from the study participants and blood samples from the babies. The level and types of antibodies will tell the team how well study participants are protected and whether they passed any protection onto their babies.

Participants will also track any vaccine side effects they experience as well as any COVID symptoms they or their babies develop during the study using a smartphone app. This will provide a more accurate understanding of the safety and effectiveness of the COVID vaccines for pregnant and postpartum people to guide future vaccine development and policies.


If you are pregnant or recently gave birth and have recently been vaccinated against COVID or plan to be vaccinated soon, you may be able to participate in this study. Visit to learn more and sign up.