Who should receive the Respiratory Syncytial Virus (RSV) vaccine during pregnancy?

RSV Vaccination During Pregnancy: Recommendations for Maternal Immunization

Pregnant persons should receive a single dose of RSVpreF vaccine (Abrysvo) during 32-36 weeks' gestation, administered seasonally (September-January in most of continental US) to prevent RSV-associated lower respiratory tract infection in infants. 1

Eligibility and Timing

• RSVpreF vaccine is specifically recommended for pregnant persons between 32 weeks 0 days and 36 weeks 6 days gestation 1
• Vaccination should occur during RSV season (September through January in most of continental US) 1, 2
• The vaccine is administered as a single 0.5 mL intramuscular dose 1
• Vaccination should be timed so that infants born during RSV season receive optimal protection 2

Efficacy and Benefits

• Maternal RSVpreF vaccination provides protection against RSV-associated lower respiratory tract infection (LRTI) in infants aged <6 months 1
• Vaccine efficacy against medically attended RSV-associated LRTI in infants is 51.3% (95% CI: 29.4-66.8%) 1
• Efficacy against severe medically attended RSV-associated LRTI in infants is 69.4% (95% CI: 44.3-84.1%) 1
• Protection against RSV hospitalization is 56.8% (95% CI: 10.1-80.7%) 1, 3
• Protection is highest in the first 3 months of life but may wane after 6 months 3

Safety Considerations

• FDA has approved the vaccine for use during 32-36 weeks' gestation after determining benefits outweigh potential risks 1
• Clinical trials showed slightly higher rates of preterm birth (<37 weeks) and hypertensive disorders in vaccine recipients compared to placebo, though differences were not statistically significant 1
• The most common adverse reactions include injection site pain, headache, muscle pain, and nausea 1
• The vaccine is contraindicated for persons with history of severe allergic reaction to any vaccine component 1
• Vaccination should be delayed in persons experiencing moderate or severe acute illness 1

Special Considerations

• At least 14 days are needed after maternal vaccination for development and transplacental transfer of maternal antibodies to protect the infant 1, 2
• Nirsevimab (monoclonal antibody) is recommended instead of maternal vaccination for:
  • Infants born to mothers who did not receive RSVpreF vaccine 1
  • Infants whose mother's vaccination status is unknown 1
  • Infants born <14 days after maternal vaccination 1, 2
  • All infants born at <34 weeks' gestation 1
  • Infants born outside RSV season (April-September) 1

Implementation Considerations

• Either maternal RSVpreF vaccination or infant nirsevimab administration is recommended, but both are not needed for most infants 1, 2
• Provider recommendation significantly increases vaccination uptake - only 32.6% of eligible pregnant women received the RSV vaccine during the 2023-24 season 4
• RSV vaccine can be administered simultaneously with other recommended vaccines for pregnant persons at different anatomic sites 2
• Adverse events after vaccination should be reported to the Vaccine Adverse Event Reporting System (VAERS) 1

Advantages of Maternal Vaccination vs. Infant Nirsevimab

• Advantages of maternal vaccination:

  • Provides protection immediately after birth 1
  • Generates polyclonal immune response potentially more resistant to RSV mutations 1

• Advantages of infant nirsevimab:

  • Protection may wane more slowly than maternal vaccine-derived antibodies 1
  • Ensures direct receipt of antibodies rather than relying on transplacental transfer 1
  • No risk for adverse pregnancy outcomes 1

The decision between maternal vaccination and infant nirsevimab should be made based on gestational age, timing of birth relative to RSV season, and individual clinical factors, with the primary goal of ensuring all infants receive protection against RSV-associated lower respiratory tract disease 1, 2.