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Getting the RSV vaccine during pregnancy can provide protection to both mother and infant. SDI Productions/Getty Images
  • Babies are at risk of severe illness from respiratory syncytial virus (RSV), which circulates in the United States in fall and winter.
  • An RSV vaccine given to pregnant people also protects babies once they are born. The vaccine is given to people who are 32 to 36 weeks pregnant during RSV season.
  • A monoclonal antibody is also available to protect infants whose mothers did not receive the maternal RSV vaccine.

With respiratory syncytial virus (RSV) season in full swing, newborn babies and infants are at risk of getting very sick from this virus.

Each year in the United States, RSV leads to approximately 100–300 deaths in children younger than 5 years old and up to 80,000 hospitalizations among that age group, according to the Centers for Disease Control and Prevention (CDC).

CDC officials released a Health Alert Network Health Advisory on December 14, warning about low vaccination rates, which could mean more people will be exposed to flu, COVID-19, and RSV this winter.

The CDC reports that hospitalizations for RSV have increased by 60% in the last 4 weeks for all age groups.

Due to low vaccination rates, healthcare professionals are encouraged to administer flu, COVID-19, and RSV vaccines to eligible patients.

Pregnant people, in particular, should consider the maternal RSV vaccine to protect their newborn.

OB-GYNs and other healthcare professionals recommend vaccinating against viruses like the flu and COVID-19 during pregnancy.

The CDC advises pregnant people to get the RSVpreF (Abrysvo) vaccine, a maternal RSV vaccine to protect newborn babies from RSV after they’re born.

Developed by Pfizer, the RSV vaccine is given to pregnant people during their third trimester, or 32–36 weeks gestation. It is the only vaccine approved by the FDA for pregnant people and is considered safe for the fetus.

Your physician should be able to provide you with a prescription for the Abrysvo vaccine made by Pfizer if you are pregnant.

Dr. Patricia Faraz, an OB-GYN at The Women’s Hospital at MemorialCare Saddleback Medical Center in Laguna Hills, CA, recommends this vaccine to all of her patients who are at the right gestational age, “especially if they have other younger children at home; or if their babies are going to be in outside day care once they’re born because those babies will be more susceptible [to getting RSV],” she told Healthline.

When a pregnant person gets the maternal RSV vaccine, their immune system responds by producing protective proteins called antibodies. This process takes about 2 weeks.

These antibodies are also passed onto the fetus. So, babies born at least 2 weeks after the mother gets the RSV vaccine will have enough antibodies to protect them from RSV.

“By providing vaccination to moms, it protects the baby,” said Dr. Elissa Malkin, assistant research professor of medicine at the George Washington University School of Medicine and Health Sciences.

According to the CDC, during the first 6 months after birth, the vaccine reduces a baby’s risk of being hospitalized due to RSV by 57%.

“Not only the tiniest preemies who are at risk but also healthy full-term kids in their first year of life who are still at risk of RSV and some of the complications, which are mostly hospitalization,” Malkin told Healthline.

The most common side effects reported by pregnant people who received the maternal RSV vaccine in clinical trials included:

A small number of pregnant people (1.8%) who received the maternal RSV vaccine experienced preeclampsia, a dangerous high blood pressure condition. This also occurred in 1.4% of pregnant people who received an inactive placebo.

There was also a small increase in the number of preterm births in pregnant people vaccinated during the clinical trials.

However, “it is not clear if this is a true safety problem related to RSV vaccine or if this occurred for reasons unrelated to vaccination,” the CDC states on its website.

The FDA is requiring Pfizer to do additional studies to examine the potential risk of pre-eclampsia and preterm birth.

If you have questions or concerns about the potential side effects of the maternal RSV vaccine, talk with your doctor or OB-GYN.

The maternal RSV vaccine is given during RSV season (September through January) to people who are 32–36 weeks pregnant. It is given as a single-dose injection in the pregnant person’s upper arm.

Two RSV vaccines are also available in the United States for adults 60 years and older:

Both older adult vaccines and the maternal RSV vaccine are given as a 0.5 milliliter dose. The GSK vaccine is only available for people over the age of 60, however.

Young children and older adults also have options available to protect them from RSV.

Another option for protecting babies from RSV is nirsevimab (Beyfortus), a monoclonal antibody developed by AstraZeneca and Sanofi.

The CDC recommends this treatment “for all infants younger than 8 months of age who are born during — or who are entering — their first RSV season.”

However, most infants will not need nirsevimab if they were born 14 or more days after their mother received the maternal RSV vaccine.

One issue with the monoclonal antibody treatment is access. Since it’s in high demand, there is a limited supply.

“So vaccinating moms is going to provide an alternate way to provide immunity to the infant, especially with the shortage of the monoclonal antibodies,” said Faraz.

RSV is a common viral infection that tends to be more common during the winter months, according to the CDC. The virus results in cold-like symptoms that are mild in most people.

Common symptoms include:

  • runny nose
  • decreased appetite
  • coughing and wheezing
  • sneezing
  • fever

Most people will recover on their own from the virus, but some, including infants, older adults, and people who are immunocompromised, are at higher risk for severe symptoms.

For children under age 1, RSV is the most common cause of pneumonia and bronchiolitis.

When is RSV season?

In most parts of the country, RSV season runs from September through January.

The season may differ in Alaska, parts of Florida, and areas outside the continental United States. If you live in one of these areas, talk with your healthcare professional about when RSV season typically occurs.

Was this helpful?

Respiratory syncytial virus (RSV) season in most parts of the United States begins in September and peaks in January.

During this time, babies are at risk of severe illness due to RSV.

A maternal RSV vaccine, given during RSV season to people who are 32–36 weeks pregnant, can also protect babies once they are born.

To offer protection to the baby, the mother must receive the vaccine 14 days or more before giving birth.

A monoclonal antibody is also available to protect babies whose mothers did not get the RSV vaccine.