At what age is the RSV (Respiratory Syncytial Virus) vaccine recommended for high-risk infants?

RSV Vaccine Age Requirements for High-Risk Infants

The RSV vaccine is recommended for high-risk infants based on specific age criteria, with palivizumab prophylaxis recommended for infants younger than 24 months with chronic lung disease (CLD), congenital heart disease (CHD), or prematurity, while nirsevimab is recommended for all infants under 8 months entering their first RSV season. 1, 2

Current RSV Prevention Options

Maternal Vaccination

• RSVpreF vaccine (Abrysvo) is administered to pregnant persons during 32-36 weeks' gestation to protect infants aged <6 months 1
• Provides passive immunity through transplacental antibody transfer
• Requires at least 14 days between vaccination and birth for adequate antibody development and transfer 1

Infant Monoclonal Antibody Options

1. Nirsevimab (Beyfortus):

   • Recommended for all infants <8 months born during or entering their first RSV season 1, 2
   • Also recommended for children aged 8-19 months at increased risk entering their second RSV season 1

2. Palivizumab (Synagis):

   • For specific high-risk groups as outlined below 1, 2
   • Administered monthly throughout RSV season (maximum 5 doses) 1

Detailed Age Requirements for High-Risk Infants

Premature Infants

• ≤28 weeks 6 days gestation: Eligible for palivizumab if <12 months of age at start of RSV season 1
• 29 weeks 0 days through 31 weeks 6 days: Eligible if <6 months of age at start of RSV season 1
• 32 weeks 0 days through 34 weeks 6 days: Eligible with additional risk factors (child care attendance or siblings <5 years) and <90 days of age at start of RSV season 1
• All premature infants <34 weeks gestation: Should receive nirsevimab regardless of maternal RSVpreF vaccination 1

Infants with Chronic Lung Disease (CLD)

• Eligible for palivizumab if <24 months of age AND receiving medical therapy (supplemental oxygen, bronchodilator, diuretic, or corticosteroid) within 6 months before RSV season 1, 2
• Maximum of 5 doses during RSV season 1

Infants with Congenital Heart Disease (CHD)

• Eligible for palivizumab if ≤24 months with hemodynamically significant cyanotic or acyanotic CHD 1, 2
• Particularly beneficial for:
  • Infants receiving medication for congestive heart failure
  • Infants with moderate-to-severe pulmonary hypertension
  • Infants with cyanotic heart disease 1

Infants with Airway/Neuromuscular Conditions

• Eligible for palivizumab if <24 months with significant congenital airway abnormalities or neuromuscular conditions that compromise handling of respiratory secretions 1, 2
• Maximum of 5 doses during the first year of life 1

Choosing Between Maternal Vaccination and Infant Prophylaxis

• Either maternal RSVpreF vaccination during pregnancy OR nirsevimab administration to the infant is recommended, but both are not needed for most infants 1
• Nirsevimab is recommended when:
  • Mother did not receive RSVpreF vaccine
  • Mother's vaccination status is unknown
  • Infant was born <14 days after maternal vaccination
  • Infant was born at <34 weeks gestation 1

Special Considerations

• Infants born during RSV season may require fewer doses of palivizumab based on timing of discharge 1
• Nirsevimab may be considered for infants born to vaccinated mothers in rare circumstances when additional protection is warranted:
  • Mothers with immunocompromising conditions
  • Conditions with reduced transplacental antibody transfer (e.g., HIV)
  • Infants who underwent cardiopulmonary bypass or ECMO
  • Infants with substantially increased risk for severe RSV disease 1

Effectiveness and Impact

Recent data shows significant reductions in RSV-associated hospitalizations after introduction of RSV prevention products, with the largest reduction (45-52%) observed among infants aged 0-2 months 3, highlighting the importance of timely implementation of these preventive measures.