What are the recommendations and side effects of the new Respiratory Syncytial Virus (RSV) vaccine, specifically Nirsevimab (Palivizumab), for pregnant individuals in the 3rd trimester?

From the Guidelines

The RSV vaccine recommended for pregnant individuals in the third trimester is the maternal RSV vaccine called Abrysvo, which is administered as a single dose between 32-36 weeks of pregnancy to protect newborns from severe RSV disease through passive antibody transfer. This vaccine is recommended to prevent RSV-associated lower respiratory tract disease in infants aged <6 months, as stated in the recommendations of the Advisory Committee on Immunization Practices - United States, 2023 1. The standard regimen is a single dose administered during this window, with common side effects including injection site reactions (pain, redness, swelling), fatigue, headache, muscle pain, and joint pain, which are typically mild to moderate and resolve within a few days 1.

Key Points

• The maternal RSV vaccine Abrysvo is recommended for pregnant individuals in the third trimester to protect newborns from severe RSV disease.
• The vaccine is administered as a single dose between 32-36 weeks of pregnancy.
• Common side effects include injection site reactions, fatigue, headache, muscle pain, and joint pain.
• Nirsevimab is actually given directly to infants after birth, not to pregnant women, while Palivizumab is used for monthly prophylaxis in high-risk infants 1.
• The maternal RSV vaccination works by allowing antibodies to cross the placenta, providing immediate protection to the newborn from birth through the first 6 months of life when they are most vulnerable to severe RSV disease 1.

Recommendations

• Either maternal RSVpreF vaccination during pregnancy or nirsevimab administration to the infant is recommended to prevent RSV-associated LRTI in infants, but both are not needed for most infants 1.
• Providers who care for pregnant persons should discuss the relative advantages and disadvantages of both maternal RSVpreF vaccination and nirsevimab and consider patient preferences when determining whether to vaccinate the pregnant person or to rely on administration of nirsevimab to the infant 1.
• Nirsevimab is recommended for infants aged <8 months born during or entering their first RSV season whose mother did not receive RSVpreF vaccine, whose mother’s receipt of RSVpreF vaccine is unknown, or who were born <14 days after maternal vaccination 1.

From the Research

RSV Vaccine and Nirsevimab for Pregnant Individuals in the 3rd Trimester

• The Centers for Disease Control and Prevention (CDC) recommends RSV vaccination for pregnant persons or administration of RSV antibody (nirsevimab) to infants aged <8 months to prevent RSV lower respiratory tract disease among infants 2.
• A study found that among 678 women at 32-36 weeks' gestation, 32.6% reported receipt of an RSV vaccine any time during pregnancy, and among 866 women with an infant born during August 2023-March 2024,44.6% reported receipt of nirsevimab by the infant 2.
• Provider recommendation for maternal vaccination or infant nirsevimab was associated with higher immunization coverage, whereas lack of a provider recommendation was the main reason for not getting RSV immunization 2.

Side Effects and Safety

• A comprehensive review of nirsevimab found that it exhibits favorable safety profiles and cost-effectiveness, with extensive clinical trials and real-world evidence demonstrating its efficacy in mitigating the incidence and severity of RSV infections in infants 3.
• A study found that preterm delivery occurred in 35 of 414 RSVpreF-vaccinated individuals (8.5%) and 43 of 233 unvaccinated individuals (18.5%), with no significant association between RSVpreF vaccination and preterm birth 4.
• Common reasons for hesitancy to use RSVpreF vaccine or nirsevimab included concerns about side effects, impacts on infants, and the immunizations being too new 5.

Recommendations

• The American College of Obstetricians and Gynecologists and the CDC have resources to assist providers in effectively communicating the importance of immunization 2.
• A review summarizes current evidence-based practices for nirsevimab and RSVpreF vaccine, highlights recommendations for delivery, and addresses challenges faced by providers during the RSV season 6.
• Health communication interventions that increase awareness about RSV immunizations and highlight their safety, effectiveness, and importance are needed to increase intended uptake 5.