What are the recommendations for Respiratory Syncytial Virus (RSV) prophylaxis in high-risk infants, such as those born prematurely or with underlying medical conditions like heart disease or lung disease?

RSV Prophylaxis Recommendations for High-Risk Infants

Palivizumab prophylaxis should be administered to infants born before 29 weeks, 0 days' gestation who are younger than 12 months at the start of RSV season, at a dose of 15 mg/kg intramuscularly every 30 days for a maximum of 5 monthly doses. 1, 2, 3

Primary Eligibility Criteria

Premature Infants Without Chronic Lung Disease

Infants born before 29 weeks, 0 days' gestation:

• Qualify for prophylaxis if younger than 12 months at RSV season start 1, 2, 4
• Should receive maximum of 5 monthly doses throughout the season 1, 2, 3
• For infants born during RSV season, fewer than 5 doses will be needed 1

Infants born at 29-35 weeks' gestation:

• Available data do not identify a clear gestational age cutoff for benefit at 29 weeks or later 1
• These infants may qualify based on other conditions (chronic lung disease or congenital heart disease) but not gestational age alone 1

Infants with Chronic Lung Disease (CLD)

First year of life:

• Infants with bronchopulmonary dysplasia requiring medical therapy (supplemental oxygen, bronchodilators, diuretics, or corticosteroids) within 6 months before RSV season start qualify for prophylaxis 1, 2, 3
• Should receive maximum of 5 monthly doses 1, 2

Second year of life:

• Only infants who continue to require medical support (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) during the 6-month period before the second RSV season qualify 1, 2
• Prophylaxis is NOT recommended if medical support has been discontinued 1, 4

Infants with Hemodynamically Significant Congenital Heart Disease

Qualifying conditions (≤12 months old):

• Infants receiving medication to control congestive heart failure who will require cardiac surgical procedures 1
• Infants with moderate to severe pulmonary hypertension 1
• Infants with cyanotic heart defects (decisions should be made in consultation with pediatric cardiologist) 1

Non-qualifying conditions:

• Hemodynamically insignificant heart disease (e.g., secundum atrial septal defect) 1

Additional High-Risk Populations

Consider prophylaxis for:

• Children with pulmonary abnormality or neuromuscular disease impairing ability to clear upper airway secretions 2
• Children with congenital abnormalities of the airway 2
• Profoundly immunocompromised children <24 months during RSV season 4
• Children <2 years undergoing cardiac transplantation during RSV season 4
• Infants with cystic fibrosis demonstrating clinical evidence of chronic lung disease AND/OR nutritional compromise in the first year of life 4

Dosing and Administration Protocol

Standard dosing:

• 15 mg/kg body weight intramuscularly every 30 days throughout RSV season 2, 4, 3
• Administer preferably in the anterolateral aspect of the thigh 3
• Avoid gluteal muscle due to risk of sciatic nerve damage 3
• Volumes >1 mL should be given as divided doses 3

Timing:

• First dose should be administered before RSV season begins (typically November in northern hemisphere) 2, 4, 3
• Continue monthly through March in most U.S. regions 4
• Maximum of 5 doses per season for qualifying infants 1, 2, 4

Special circumstances:

• Infants in neonatal units may receive first dose 48-72 hours before discharge or promptly after discharge 2
• Children undergoing cardiopulmonary bypass should receive an additional dose as soon as possible after the procedure, even if sooner than one month from previous dose 2, 3
• This is critical because palivizumab serum concentration decreases by 58% following cardiopulmonary bypass 2, 3

Critical Limitations and Pitfalls to Avoid

What palivizumab does NOT do:

• Has NO therapeutic benefit for treating established RSV infection—it is ONLY for prevention 1, 4, 3
• Should NOT be used for primary asthma prevention or to reduce subsequent wheezing episodes 1, 2
• Has limited effect on RSV hospitalizations on a population basis, no measurable effect on mortality, and minimal effect on subsequent wheezing 1

When to discontinue:

• If an infant receiving monthly prophylaxis experiences a breakthrough RSV hospitalization, discontinue prophylaxis due to extremely low likelihood of second RSV hospitalization in the same season 2

Dosing errors to avoid:

• Do NOT dilute the product 3
• Do NOT shake or vigorously agitate the vial 3
• Single-dose vial only—do NOT re-enter vial after withdrawal; discard unused portion 3
• Efficacy at doses <15 mg/kg or less frequent than monthly dosing has not been established 3

Complementary Prevention Measures

All high-risk infants should:

• Avoid exposure to crowds and situations where contact with infected individuals cannot be controlled 2, 4
• Restrict participation in group child care during RSV season when feasible 2, 4
• Have no exposure to tobacco smoke 2, 4
• Receive influenza vaccine (starting at 6 months) along with all household contacts 2, 4
• Practice careful hand hygiene by all caregivers 2
• Be breastfed when possible to decrease risk of lower respiratory tract disease 2

Evidence Quality and Clinical Impact

The recommendation to limit prophylaxis to infants <29 weeks' gestation represents a significant narrowing from previous guidelines that included infants up to 35 weeks' gestation 1. This change reflects the 2014 American Academy of Pediatrics determination that palivizumab has "limited clinical benefit," with only a 45-55% reduction in RSV hospitalizations and no measurable effect on mortality 1, 3, 5. The cost-benefit analysis drove this more restrictive approach, prioritizing only those at highest risk of severe disease 1.