You may have heard that the Centers for Disease Control and Prevention (CDC) recently recommended a new vaccine for use in the third trimester of pregnancy. Known as AbrysvoTM, the vaccine helps protect newborns from severe cases of respiratory syncytial virus (RSV). RSV is the leading cause of infant hospitalization in the United States, with 58,000–80,000 hospitalizations occurring each year in children younger than 5 years. Even more alarming, 100-300 children under the age of 5 die from RSV each year. With these statistics in mind, this new RSV vaccine is exciting news for infants and their families.
Ava, 24 weeks along with her first pregnancy, contacted the MotherToBaby live chat service early one morning with some questions about the new RSV vaccine. First, he wanted to understand how vaccinating a pregnant woman might protect a baby. As a Teratogen Information Specialist, I was happy to answer this question for Ava. I started by explaining that when a person is vaccinated, their body produces antibodies. These antibodies protect the body from actual infection if a person is exposed to the virus or bacteria later in life. During pregnancy, antibodies produced by a pregnant woman after vaccination can cross the placenta and pass to the developing baby, providing the newborn with some protection from infection during the first few months of life.
I went on to explain that although the RSV vaccine is new, the idea of getting a shot during pregnancy to protect the baby (called “passive immunity”) has been around for quite some time. The Tdap vaccine, which protects against tetanus, diphtheria and whooping cough (whooping cough), has been recommended for use in pregnancy since 2011. Pertussis is another infection that can be very serious for newborns, so protection against birth as a result maternal vaccination is ideal. The flu shot and the COVID-19 vaccine can also pass antibodies to the developing baby during pregnancy. This is great news, as newborns can’t get their own flu or COVID-19 shots until 6 months of age and must rely on passive immunity in the meantime.
Ava then had a question about it never should get the RSV vaccine. She had plans to get her flu shot and Tdap shot at her next prenatal visit at 28 weeks. He wanted to know if he could get the RSV shot at the same time. Although these three vaccines (along with the updated COVID-19 vaccine) can all be given on the same day, the RSV vaccine should be given at a specific time in order to pass as many antibodies to the baby as possible. Experts recommend that the RSV vaccine be given between 32 and 36 weeks of pregnancy. This allows enough time for the RSV antibodies to pass to the baby before delivery.
With this recommendation in mind, Ava decided that her 32-week prenatal appointment would be the perfect time to get the RSV shot. She had seen firsthand how serious RSV can be when her 1-month-old niece was hospitalized with RSV last winter, so she didn’t want to take any chances by forgetting to get the RSV vaccine during her pregnancy.
Before we ended the conversation, I mentioned to Ava that there is also a vaccine called nirsevimab (BeyfortusTM) that can be given directly to babies under 8 months of age. Also known as a monoclonal antibody, this vaccine is another way to protect infants from severe RSV disease. Most babies don’t need nirsevimab if their mom got the RSV vaccine during pregnancy. I suggested that Ava talk to her health care provider about the pros and cons of both options.
Although remembering to get another vaccine in pregnancy may feel like one more thing a pregnant woman has to add to her never-ending to-do list, the decision to get vaccinated can prevent serious complications from RSV and potentially even save the baby’s life. Here at MotherToBaby, we’re happy to review current pregnancy vaccine recommendations and answer any questions you may have. Feel free to call, chat, text, or email with any questions about the RSV vaccine or other exposures during pregnancy. You can also see our newest newsletter about this vaccine here
Bibliographical references:
Centers for Disease Control and Prevention. 2023. RSV vaccination for pregnant women. Available in:
Centers for Disease Control and Prevention. 2023. RSV Surveillance & Research. Available in:
