Maternal Respiratory Syncytial Virus Vaccination

Key Recommendations

• The American College of Obstetricians and Gynecologists recommends a single dose of Pfizer’s bivalent RSVpreF vaccine (Abrysvo) using seasonal administration, to prevent RSV lower respiratory tract infection (LRTI) in infants for eligible pregnant individuals meeting the following criteria:
  • are between 32 0/7 and 36 6/7 weeks of gestation,
  • do not have a planned delivery within 2 weeks,
  • did not receive the maternal RSV vaccine during a previous pregnancy, and 
  • are not planning to have their infant receive a monoclonal antibody, nirsevimab or clesrovimab.
• In most of the continental United States, based on the seasonal circulation of RSV, pregnant patients are eligible to receive the maternal RSV vaccine from September 1 through January 31 to provide protection during the time of circulation of RSV. 
• Administration of the RSV vaccine can vary in jurisdictions within or outside the continental United States. In jurisdictions where RSV seasonality differs from most of the United States, CDC recommends that health care professionals follow state, local, or territorial RSV epidemiology and guidance for determining the optimal timing of administration of the RSV vaccine.
• It is currently not recommended that pregnant patients who received the maternal RSV vaccine during their last pregnancy receive an additional dose during a subsequent pregnancy. Clinicians should review the patient’s medical record to confirm vaccination status. For patients vaccinated in a previous pregnancy, their infants should receive a monoclonal antibody. 
• Clinicians should counsel patients about the maternal RSV vaccine and the monoclonal antibodies as safe and effective ways to prevent severe LRTI caused by RSV in infants. Clarify for patients that the infant needs a monoclonal antibody at birth if the pregnant patient declines maternal RSV vaccination. Counsel patients about the maternal RSV vaccine in the antepartum stage to allow the patient time to consider this vaccination and the other recommended maternal vaccines (COVID-19, influenza, and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis [Tdap]) and provide the opportunity to ask questions during prenatal visits.
• Patient preferences should be considered when determining whether to administer the maternal RSV vaccine or to opt for administration of a monoclonal antibody to the infant after birth. There is no preferential recommendation for use of maternal vaccine, clesrovimab, or nirsevimab.
• Supply of monoclonal antibodies could be a key component of conversations and decision making with patients regarding maternal vaccination. Maternal vaccination should be encouraged, particularly in areas where monoclonal antibodies are unavailable at birthing hospitals.
• ACOG encourages clinicians to stock and, ideally, administer the maternal RSV vaccine along with all routinely recommended maternal vaccines in their offices.
• It is critically important that pregnant patients receive all recommended vaccines. For pregnant patients who have been admitted to the hospital, clinicians should review the patients’ vaccination status and consider offering missed maternal vaccinations at that time.
• It is important that clinicians document receipt or declination of maternal RSV vaccination in the patient’s medical record. Electronic medical records (EMRs) can be used to track patients’ vaccination status and can help clinicians make informed decisions. It is recommended that clinicians advocate within their health systems for the creation of EMR alerts for vaccines, as this can help to communicate whether a newborn will need a monoclonal antibody. 
• The only RSV vaccine approved for use during pregnancy is Pfizer’s bivalent RSVpreF vaccine, Abrysvo.
• The following vaccines are not approved for use in pregnancy: GSK’s RSV vaccine, Arexvy, and Moderna’s RSV vaccine, MRESVIA.
• Clinicians might receive questions about the FDA’s January 2025 requirement for safety labeling changes to the Prescribing Information for Abrysvo describing an increased risk of Guillain-Barré syndrome (GBS). It is important to explain to patients that this safety labeling update is due to the results of an observational study suggesting an increased risk of GBS during the 42 days following vaccination in a population of people aged 65 years and older only. Guillain-Barré syndrome has not been reported after vaccination during pregnancy. The FDA has determined that the benefits of vaccination with Abrysvo continue to outweigh its risks (FDA 2025; Lloyd 2024).

Background

Respiratory syncytial virus is a common respiratory virus that usually causes upper respiratory illness, but RSV can be a serious LRTI, presenting as bronchiolitis or pneumonia, for some groups, including infants and older adults. Currently, there is no antiviral treatment for severe RSV disease except for highly immunocompromised patients, and there is no licensed pediatric vaccine.

Respiratory syncytial virus is one of the most common causes of childhood respiratory illness and results in annual outbreaks of respiratory illnesses in all age groups. An estimated 58,000–80,000 children under age 5 years are hospitalized each year nationwide because of RSV infection, with some requiring oxygen, intravenous fluids, or mechanical ventilation. The hospitalization rate is highest among infants 0–6 months of age (CDC 2025). Each year, an estimated 100–300 children younger than age 5 years, particularly if under age 6 months, die because of RSV in the United States (Jones 2023). Furthermore, RSV disease in early life has been associated with complications such as secondary bacterial infections, inappropriate use of antibiotics, and long-term respiratory illness, including recurrent wheezing and asthma.

RSV Prevention: Maternal Vaccination

On August 21, 2023, the FDA approved the first RSV vaccine, Abrysvo, for use in pregnant individuals to protect newborns and infants against severe RSV disease in the first 6 months after birth. The unadjuvanted bivalent (RSV A and B) preF protein-based vaccine was approved by the FDA to be administered as a single dose between 32 0/7 and 36 6/7 weeks of gestation (AAP 2014).

On September 22, 2023, the CDC’s Advisory Committee on Immunization Practices (ACIP) voted to recommend a single dose of maternal RSV vaccination for pregnant people at 32 0/7 through 36 6/7 weeks of gestation, using seasonal administration, to prevent RSV LRTI in infants (Fleming-Dutra 2023).

Importantly, while there are two other RSV vaccines approved for use in older adults (manufactured by GSK and Moderna), these are not approved for use in pregnancy. Currently, the only RSV vaccine approved for use in pregnancy is Pfizer’s bivalent RSVpreF vaccine, Abrysvo.

Vaccine Efficacy

In the pivotal phase 3 clinical trial, among approximately 3,500 pregnant individuals who received Abrysvo, compared to approximately 3,500 pregnant individuals who received a placebo, Abrysvo reduced the risk of severe LRTI in infants by 81.8% within 90 days after birth, and 69.4% within 180 days after birth. Additionally, in a subgroup of pregnant individuals who were at 32 through 36 weeks of gestation, of whom approximately 1,500 received Abrysvo and 1,500 received placebo, Abrysvo reduced the risk of severe LRTI by 91.1% within 90 days after birth when compared to placebo. Within 180 days after birth, Abrysvo reduced the risk of LRTI by 57.3% and by 76.5% for severe LRTI, when compared to placebo (AAP 2014).

Vaccine Effectiveness

Several post-implementation studies from Argentina and the United Kingdom after the first season of maternal vaccine implementation demonstrated significant reductions in infant severe RSV LRTI and hospitalization in the first 6 months of life, and markedly in the first 3 months of life, with additional findings of decreased length of stay and severity of disease in some studies, consistent with the results of the phase 3 clinical trial (Razzini 2025; Perez 2025; Gentile 2025; Williams 2025).

Vaccine Safety

In Fall 2023, the vaccine safety surveillance platform of the CDC, V-safe, was expanded to include the maternal RSV vaccine, and as with other vaccines, the side effects most commonly reported in V-safe by pregnant individuals who received the RSV vaccine were pain at the injection site, headache, muscle pain, and nausea (AAP 2014). These reports are consistent with pre-licensure studies (Moro 2024).

The prescribing information for Abrysvo includes a warning to inform patients that a non-statistically significant, numerical imbalance in preterm births in Abrysvo recipients (5.7%) occurred compared to those who received placebo (4.7%) in the clinical trial. This imbalance was only seen in trial participants residing in low- to middle-income countries with no temporal association to vaccination or association with other adverse events in the mother or the newborn. Thus, the data available at the time of licensure were considered insufficient to establish or exclude a causal relationship between preterm birth and Abrysvo. The U.S. Food and Drug Administration warning informs health care professionals that to mitigate the theoretical risk of preterm birth following administration of RSV vaccine before 32 weeks of gestation, Abrysvo should be administered as indicated in eligible pregnant individuals at 32 through 36 weeks of gestation (Jones 2023). Findings of post-authorization safety surveillance in the Vaccine Safety Datalink (VSD) observed that the incidence of preterm births was 4.1% among pregnant persons who received Abrysvo during the 2023–2024 respiratory season (Moro 2024). This rate is within the expected range of the incidence of preterm births (3.1–6.1%) before introduction of this vaccine, and not different from the rate observed in women who did not receive the RSV vaccine during pregnancy. Among reports received in the Vaccine Adverse Event Reporting System (VAERS), the most frequent adverse events reported were pregnancy-specific conditions (eg, preterm delivery) after the maternal Pfizer RSV vaccine, with no causal association. These reports are as expected for a vaccine recommended at 32–36 weeks of gestation. These findings are also consistent with a retrospective observational cohort study of pregnant individuals who delivered at 32 weeks of gestation or later and found that the RSVpreF vaccine was not associated with an increased risk of preterm birth and perinatal outcomes (Son 2024).

There are conflicting data on whether there is a slight increase in hypertensive disorders of pregnancy for women who received the RSV vaccine during pregnancy compared to those who did not receive the vaccine. Son et al reported in a retrospective observational cohort from two hospitals in New York that hypertensive disorders of pregnancy were more frequent only when evaluating the data using a time-dependent Cox covariate regression analysis but not when using a logistic regression analysis (Son 2024). Data from the CDC's VSD continued to show a potential increased incidence of hypertensive disorders of pregnancy in patients receiving the RSV vaccine during pregnancy (DeSilva 2025). From the VSD, a cohort of 115,000 pregnant patients who received RSV vaccine during the 2023–2024 RSV seasons were matched to those who had not received vaccine. The propensity score matching included the site, maternal age, gestational age by week, race/ethnicity, and medical comorbidities, including hypertension and diabetes mellitus. Notably, parity was not included as a covariate in the propensity score matching in this trial. The VSD found that women who received the RSV vaccine had a 17.4% incidence of hypertensive disorders of pregnancy (inclusive of gestational hypertension and preeclampsia) versus 15.3% in unvaccinated matched controls (absolute risk reduction [ARR] 1.09 [1.03–1.15]) and vaccinated women had a 8.9% incidence of preeclampsia versus 7.6% in unvaccinated controls (ARR 1.12 [1.03–1.21]). The studies that have demonstrated this association appear to find predominantly diagnoses of gestational hypertension and not severe forms of preeclampsia.

The phase 3 double-blinded randomized controlled trial of maternal RSV vaccine did not find a significant increase in preeclampsia in pregnant women receiving the vaccine (1.8% of participants in the vaccine group and 1.4% of those in the placebo group) (Kampmann 2023).

The CDC has reaffirmed the warning that the RSV vaccine may be associated with an increase in hypertensive disorders of pregnancy. This finding may be related to residual confounding variables, and further studies are needed to determine if this is a causal link. These findings do not preclude the use of the RSVpreF vaccine in pregnancy, given its substantial efficacy in preventing severe RSV disease in infants and overall safety profile.

A post-marketing observational study suggested an increased risk of GBS (an estimated nine excess cases of GBS per million doses of Abrysvo) during the 42 days following vaccination among people 65 years of age and older. However, available evidence is insufficient to establish a causal relationship. While an increase in GBS has not been seen in pregnancy, in January 2025, the FDA required safety labeling changes to the Prescribing Information for Abrysvo to include this information. The FDA has determined that the benefits of vaccination with Abrysvo continue to outweigh its risks. The FDA has also required the manufacturer of Abrysvo to conduct a study to assess the risk of GBS following administration of Abrysvo in pregnant individuals (FDA 2025; Lloyd 2024).

The Centers for Disease Control and Prevention and FDA will continue to monitor maternal RSV vaccine safety in VAERS, V-safe, and VSD.

RSV Prevention: Monoclonal Antibody Products

There are now two long-acting monoclonal antibodies for the prevention of severe RSV disease in infants from birth to 7 months of age: nirsevimab and clesrovimab. Nirsevimab was approved and recommended in 2023, and clesrovimab was approved in 2025.

One dose of nirsevimab or clesrovimab is now recommended for all infants younger than 8 months, born during—or entering—their first RSV season, if their mothers did not receive the maternal RSVpreF vaccine or infants were born 14 days or earlier after maternal vaccination. The optimal timing for administration is at birth or within the first week of birth when infants are born during the RSV season. Infants who do not receive a monoclonal antibody at birth can receive it at any time through 7 months of age (before they turn 8 months), regardless of gestational age at birth or the presence of underlying medical conditions. It is recommended that infants born to patients who were vaccinated with the maternal RSV vaccine during a prior RSV season, receive a monoclonal antibody as pregnant women are not currently eligible to receive maternal vaccine more than once. Administration of monoclonal antibodies is important when infants are born less than 14 days after maternal vaccination as there might not be sufficient time for adequate antibody transfer, when there is any concern that the maternal immune response to the vaccine will be inadequate, or when there is any condition that could affect the transplacental transfer of antibodies.

Nirsevimab was effective against RSV-associated hospitalization among infants in their first RSV season during the 2023–2024 RSV season by 91% as per early reporting in NSVN (New Vaccine Surveillance Network) and 98% in VISION (Virtual SARS-CoV-2, Influenza, and Other respiratory viruses Network) (Payne 2024; Zar 2025).

Another monoclonal antibody product, palivizumab, is no longer routinely recommended for use and will be discontinued as of December 31, 2025 (AAP 2025).

ACOG Recommendations

The American College of Obstetricians and Gynecologists recommends a single dose of Pfizer’s RSV vaccine (Abrysvo) for eligible pregnant individuals between 32 0/7 and 36 6/7 weeks of gestation who do not have a planned delivery within 2 weeks, using seasonal administration, to prevent RSV LRTI in infants. Pregnant individuals who did not receive the maternal RSV vaccine during a previous pregnancy are eligible to receive the maternal vaccine during the respiratory season.

For most of the continental United States, RSV season occurs from October through March. Respiratory syncytial virus vaccination is recommended for eligible pregnant individuals during the months of September through January. In jurisdictions with seasonality that differs from most of the continental United States (eg, Alaska, jurisdictions with tropical climates), health care professionals should follow state, local, or territorial guidance on the timing of administration (Fleming-Dutra 2023).

It is not recommended that pregnant patients who received the maternal RSV vaccine during a previous pregnancy receive an additional dose during a subsequent pregnancy. However, their infants should receive a monoclonal antibody in the hospital setting before discharge for infants born shortly before or during the RSV season. Otherwise, clinicians should aim for administration of a monoclonal antibody in the first week of life.

Most newborns and infants should not receive both maternal vaccination and monoclonal antibody administration. However, because the earliest time of vaccination is 32 0/7 weeks, and at least 14 days are needed from the time of maternal vaccination for development and transplacental transfer of maternal antibodies to protect the infant, infants born at less than 14 days after receiving the vaccine should receive a monoclonal antibody regardless of maternal vaccination status (Fleming-Dutra 2023).

For immunization resources and additional clinical guidance, please visit the Physician Tools for Immunization page.

Counseling

All infants are recommended to be protected from severe RSV disease by either the maternal RSV vaccine or a monoclonal antibody for the RSV season. Both are safe and effective interventions available for RSV prevention in infants, and the CDC and ACOG have not recommended a preferred approach.

Pregnant patients should be counseled about RSV and the risk of infection to their newborns and young infants. Clinicians should explain the difference between RSV, influenza, and COVID-19, and the need for different vaccines to protect against each of these infections. Clinicians should clarify for patients that the infant needs a monoclonal antibody at birth if the pregnant patient declines maternal RSV vaccination. Counsel patients about the maternal RSV vaccine in the antepartum stage to allow the patient time to consider this vaccination and the other recommended maternal vaccines (COVID-19, influenza, and Tdap) as well as ask questions during prenatal visits. For pregnant patients who have been admitted to the hospital, clinicians should review the patients’ vaccination status and consider offering missed maternal vaccinations at that time.

Clinicians should counsel patients about the safety profile of the vaccine and the benefits of maternal RSV vaccination as a safe and effective way to prevent severe LRTI caused by RSV in infants through age 6 months. However, it is important to verify through reviewing the medical record that patients have not received another dose of the maternal RSV vaccine in a previous pregnancy.

Clinicians should also counsel patients regarding a monoclonal antibody as a safe and effective option for newborns if the maternal RSV vaccine is not received during pregnancy or if the patient was previously vaccinated during pregnancy. There is no preferential recommendation for the use of clesrovimab versus nirsevimab. If there is a limited supply of nirsevimab or clesrovimab at any point during the season, discussions concerning the benefit of maternal vaccination should occur.

Patient preferences should be considered when determining whether to administer the maternal RSV vaccine or not to administer the maternal RSV vaccine and rely on administration of a monoclonal antibody to the infant after birth. Unvaccinated patients should be made aware that if they plan to have their newborn receive nirsevimab or clesrovimab, they do not need to receive the maternal RSV vaccine during pregnancy.

See Box 1 for additional counseling support for clinicians.

Storage and Administration

ACOG encourages clinicians to stock and, ideally, administer all recommended vaccines in their offices. Studies show that immunization rates are higher when a trusted clinician can strongly recommend, offer and administer the vaccine during the same visit, as opposed to recommending vaccination and referring the patient elsewhere to receive the vaccine. Influenza and Tdap vaccines are routinely offered and administered by a majority of practices, while other vaccines are not as commonly stocked, leaving significant gaps in coverage (CDC 2024, O’Leary 2019). When clinicians make immunizations an integral part of their practice and routinely recommend and administer indicated vaccine, they help to increase vaccination rates for pregnant people.

Many obstetrician–gynecologists also perceive a lack of reimbursement as a major barrier to including immunization services in their practices (Leddy 2009). However, with proper documentation and coding, these services can be reported to third-party payers and reimbursement can be received. The practice should adhere to basic coding principles when billing for immunization services. In general, the appropriate vaccine product code should always be reported along with the appropriate Current Procedural Terminology (CPT) vaccine administration code.

Obstetrician–gynecologists have a unique opportunity to reduce the frequency of vaccine-preventable diseases. To accomplish that goal, clinicians must be aware of current vaccine recommendations, educate patients about vaccination, encourage patients to be vaccinated, and institute systems in the office to integrate vaccination into the routine running of their practice.

For more information on documentation and coding, please visit Immunization Coding for Obstetrician–Gynecologists and Obtain Maximum Reimbursement for the Maternal Respiratory Syncytial Virus (RSV) Vaccine (Abrysvo): Administration, Storage and Coding Tips for Obstetricians.

Co-administration with Other Maternal Vaccines

It is critically important that pregnant patients receive all recommended vaccines. Maternal RSV vaccine can be administered at the same time as other vaccines routinely recommended during pregnancy (Fleming-Dutra 2023).

It is recommended that clinicians discuss all vaccines recommended during pregnancy (COVID-19, influenza, Tdap, RSV) with their patients at the first prenatal encounter to plan for when patients are eligible to receive them and to reduce vaccine burden. For pregnant patients who have been admitted to the hospital, clinicians should review the patients’ vaccination status and consider offering missed maternal vaccinations at that time.

Documentation

Documentation of vaccine receipt or declination is an essential component of any immunization program. All vaccines received or declined should be documented in the patient’s chart and the state immunization information system. As such, clinicians should document receipt or declination of maternal RSV vaccination in the patient’s medical chart. Documentation of RSV vaccination or declination is especially critical because of the relationship between maternal RSV vaccination and infant monoclonal antibody administration. Hospitals and pediatric care professionals will need to know the maternal RSV vaccination status to counsel patients appropriately about the monoclonal antibody for the newborn. Electronic medical records can be used to track patients’ vaccination status and can help clinicians make informed decisions. It is recommended that clinicians advocate within their health systems for the creation of EMR alerts for vaccines, as this can help to communicate whether a newborn will need a monoclonal antibody.

For more information on documentation and coding, please visit Immunization Coding for Obstetrician–Gynecologists and Obtain Maximum Reimbursement for the Maternal Respiratory Syncytial Virus (RSV) Vaccine (Abrysvo): Administration, Storage and Coding Tips for Obstetricians.