RSV Vaccination in Late Pregnancy Significantly Reduces Infant Hospitalizations

Recent studies confirm that maternal vaccination against respiratory syncytial virus (RSV) during pregnancy substantially lowers the risk of severe illness in newborns, offering critical protection during the most vulnerable early months of life.

How Maternal RSV Vaccination Protects Infants

RSV is a leading cause of respiratory illness in infants, often resulting in bronchiolitis and pneumonia that require hospitalization. When a pregnant person receives an RSV vaccine, antibodies are transferred to the fetus across the placenta, providing passive immunity that safeguards the baby after birth. This protection is especially vital for infants under six months old, who are at highest risk for severe RSV complications.

According to a nationwide cohort study from France published in JAMA, infants whose mothers received the RSVpreF vaccine (Abrysvo) during late pregnancy had a significantly reduced risk of RSV-associated hospitalization compared to unvaccinated mothers. The study analyzed data from over 42,000 infants born between September and December 2024, followed through February 2025. Among 481 RSV-associated hospitalizations, 44% occurred in infants protected by maternal vaccination, while 56% occurred in those receiving nirsevimab, a long-acting monoclonal antibody. This indicates maternal vaccination provided substantial protection, though nirsevimab demonstrated slightly greater effectiveness in preventing hospitalization.

Further supporting evidence comes from a hospital-based retrospective cohort study in Buenos Aires, which found the RSV maternal vaccine was 87.2% effective in preventing pediatric intensive care unit (PICU) admissions, and 88.6% effective in reducing extended hospital stays for infants under six months. These findings underscore the vaccine’s role in mitigating severe outcomes beyond just preventing hospitalization.

Comparing Maternal Vaccination and Nirsevimab

While both maternal vaccination and nirsevimab are effective strategies for preventing RSV in infants, they work through different mechanisms. Maternal vaccination stimulates the mother’s immune system to produce antibodies that cross the placenta, offering protection that begins at birth. Nirsevimab, administered as a single injection to infants, provides direct passive immunity through a long-acting monoclonal antibody.

The French study noted that even though maternal vaccination reduced hospitalization risk, nirsevimab was associated with lower risks of severe outcomes, including PICU admission (adjusted hazard ratio [aHR], 0.58), ventilator support (aHR, 0.57), and oxygen therapy (aHR, 0.56). Although, both approaches are valuable tools in the public health arsenal against RSV, and their use may be complementary depending on individual circumstances and healthcare settings.

Public Health Impact and Recommendations

The introduction of RSV prevention products—including maternal vaccines and nirsevimab—has marked a significant advancement in infant health. During the 2024–2025 RSV season, widespread availability of these interventions contributed to lower hospitalization rates among infants and young children compared to previous seasons. Health authorities now recommend maternal RSV vaccination as a standard component of prenatal care, ideally administered between 32 and 36 weeks of gestation to maximize antibody transfer.

Ongoing surveillance continues to monitor the long-term effectiveness and safety of these interventions, but current evidence strongly supports their use in reducing the burden of RSV on families and healthcare systems. Expectant parents are encouraged to discuss RSV vaccination options with their healthcare providers to ensure optimal protection for their newborns.

Frequently Asked Questions

When is the best time to receive the RSV vaccine during pregnancy?

The optimal window for maternal RSV vaccination is between 32 and 36 weeks of gestation. This timing allows sufficient time for antibody production and transfer to the fetus before birth, ensuring the newborn is protected during the early months when RSV risk is highest.

Can the RSV vaccine be given alongside other prenatal vaccines?

Yes, the RSV vaccine can be administered during the same visit as other recommended prenatal vaccines, such as those for influenza, tetanus-diphtheria-pertussis (Tdap), and COVID-19. There is no known interference between these vaccines, and co-administration is considered safe and effective.

Is maternal RSV vaccination safe for both mother and baby?

Clinical trials and real-world surveillance have shown the RSV maternal vaccine to have a favorable safety profile. Common side effects are typically mild and include injection site pain, headache, or muscle aches. Serious adverse events are rare, and ongoing monitoring continues to confirm the vaccine’s safety for pregnant individuals and their infants.

Key Takeaways

• Maternal RSV vaccination during late pregnancy significantly reduces the risk of infant hospitalization due to RSV.

• The vaccine works by transferring protective antibodies to the fetus, providing passive immunity from birth.

• Studies show effectiveness rates of up to 88.6% in preventing extended hospital stays and 87.2% in avoiding PICU admissions for infants under six months.

• Both maternal vaccination and nirsevimab are effective RSV prevention strategies, with nirsevimab showing slightly stronger protection against severe outcomes in some studies.

• Health experts recommend RSV vaccination as part of routine prenatal care between 32 and 36 weeks gestation.

Looking Ahead

As RSV prevention strategies continue to evolve, maternal vaccination remains a cornerstone of efforts to protect infants from this common yet potentially serious virus. With proven effectiveness and a strong safety profile, the RSV vaccine offers expectant parents a powerful way to safeguard their children’s health from the particularly first days of life. Continued research and real-world data will further refine our understanding of how best to utilize these tools to minimize RSV-related morbidity and mortality in vulnerable populations.

RSV Vaccination in Late Pregnancy Significantly Reduces Infant Hospitalizations

Recent studies confirm that maternal vaccination against respiratory syncytial virus (RSV) during pregnancy substantially lowers the risk of severe illness in newborns, offering critical protection during the most vulnerable early months of life.

How Maternal RSV Vaccination Protects Infants

RSV is a leading cause of respiratory illness in infants, often resulting in bronchiolitis and pneumonia that require hospitalization. When a pregnant person receives an RSV vaccine, antibodies are transferred to the fetus across the placenta, providing passive immunity that safeguards the baby after birth. This protection is especially vital for infants under six months old, who are at highest risk for severe RSV complications.

According to a nationwide cohort study from France published in JAMA, infants whose mothers received the RSVpreF vaccine (Abrysvo) during late pregnancy had a significantly reduced risk of RSV-associated hospitalization compared to unvaccinated mothers. The study analyzed data from over 42,000 infants born between September and December 2024, followed through February 2025. Among 481 RSV-associated hospitalizations, 44% occurred in infants protected by maternal vaccination, while 56% occurred in those receiving nirsevimab, a long-acting monoclonal antibody. This indicates maternal vaccination provided substantial protection, though nirsevimab demonstrated slightly greater effectiveness in preventing hospitalization.

Further supporting evidence comes from a hospital-based retrospective cohort study in Buenos Aires, which found the RSV maternal vaccine was 87.2% effective in preventing pediatric intensive care unit (PICU) admissions and 88.6% effective in reducing extended hospital stays for infants under six months. These findings underscore the vaccine’s role in mitigating severe outcomes beyond just preventing hospitalization.

Comparing Maternal Vaccination and Nirsevimab

While both maternal vaccination and nirsevimab are effective strategies for preventing RSV in infants, they work through different mechanisms. Maternal vaccination stimulates the mother’s immune system to produce antibodies that cross the placenta, offering protection that begins at birth. Nirsevimab, administered as a single injection to infants, provides direct passive immunity through a long-acting monoclonal antibody.

The French study noted that although maternal vaccination reduced hospitalization risk, nirsevimab was associated with lower risks of severe outcomes, including PICU admission (adjusted hazard ratio [aHR], 0.58), ventilator support (aHR, 0.57), and oxygen therapy (aHR, 0.56). However, both approaches are valuable tools in the public health arsenal against RSV, and their use may be complementary depending on individual circumstances and healthcare settings.

Public Health Impact and Recommendations

The introduction of RSV prevention products—including maternal vaccines and nirsevimab—has marked a significant advancement in infant health. During the 2024–2025 RSV season, widespread availability of these interventions contributed to lower hospitalization rates among infants and young children compared to previous seasons. Health authorities now recommend maternal RSV vaccination as a standard component of prenatal care, ideally administered between 32 and 36 weeks of gestation to maximize antibody transfer.

Ongoing surveillance continues to monitor the long-term effectiveness and safety of these interventions, but current evidence strongly supports their use in reducing the burden of RSV on families and healthcare systems. Expectant parents are encouraged to discuss RSV vaccination options with their healthcare providers to ensure optimal protection for their newborns.

Frequently Asked Questions

When is the best time to receive the RSV vaccine during pregnancy?

The optimal window for maternal RSV vaccination is between 32 and 36 weeks of gestation. This timing allows sufficient time for antibody production and transfer to the fetus before birth, ensuring the newborn is protected during the early months when RSV risk is highest.

Can the RSV vaccine be given alongside other prenatal vaccines?

Yes, the RSV vaccine can be administered during the same visit as other recommended prenatal vaccines, such as those for influenza, tetanus-diphtheria-pertussis (Tdap), and COVID-19. There is no known interference between these vaccines, and co-administration is considered safe and effective.

Is maternal RSV vaccination safe for both mother and baby?

Clinical trials and real-world surveillance have shown the RSV maternal vaccine to have a favorable safety profile. Common side effects are typically mild and include injection site pain, headache, or muscle aches. Serious adverse events are rare, and ongoing monitoring continues to confirm the vaccine’s safety for pregnant individuals and their infants.

Key Takeaways

• Maternal RSV vaccination during late pregnancy significantly reduces the risk of infant hospitalization due to RSV.
• The vaccine works by transferring protective antibodies to the fetus, providing passive immunity from birth.
• Studies show effectiveness rates of up to 88.6% in preventing extended hospital stays and 87.2% in avoiding PICU admissions for infants under six months.
• Both maternal vaccination and nirsevimab are effective RSV prevention strategies, with nirsevimab showing slightly stronger protection against severe outcomes in some studies.
• Health experts recommend RSV vaccination as part of routine prenatal care between 32 and 36 weeks gestation.

Looking Ahead

As RSV prevention strategies continue to evolve, maternal vaccination remains a cornerstone of efforts to protect infants from this common yet potentially serious virus. With proven effectiveness and a strong safety profile, the RSV vaccine offers expectant parents a powerful way to safeguard their children’s health from the very first days of life. Continued research and real-world data will further refine our understanding of how best to utilize these tools to minimize RSV-related morbidity and mortality in vulnerable populations.