What is the role of Palivizumab (palivizumab) in preventing respiratory syncytial virus (RSV) infection in high-risk infants?

Role of Palivizumab in Preventing RSV Infection in High-Risk Infants

Palivizumab is indicated only for specific high-risk pediatric populations, including infants born before 29 weeks' gestation who are younger than 12 months at RSV season start, those with chronic lung disease requiring medical treatment, and those with hemodynamically significant congenital heart disease. 1

Patient Selection Criteria

Recommended for Prophylaxis:

1. Premature Infants

   • Infants born before 29 weeks, 0 days' gestation who are younger than 12 months at the start of RSV season 2, 1
   • Infants born at 29 weeks or later generally do not qualify unless they have other qualifying conditions 1

2. Chronic Lung Disease (CLD)

   • Infants and children younger than 24 months with CLD who received medical therapy (supplemental oxygen, bronchodilator, diuretic or chronic corticosteroid therapy) within 6 months before the start of RSV season 2, 1
   • During the second year of life, prophylaxis is only recommended for children with CLD who continue to require medical support 1

3. Congenital Heart Disease (CHD)

   • Children 12 months or younger with hemodynamically significant CHD 2, 1
   • Particularly those with:
     • Acyanotic heart disease receiving medication for congestive heart failure
     • Moderate to severe pulmonary hypertension
     • Cyanotic heart defects 1

Not Recommended for Prophylaxis:

• Infants with hemodynamically insignificant heart disease (e.g., secundum atrial septal defect, small ventricular septal defect) 2
• Infants with lesions adequately corrected by surgery (unless they continue to require medication for congestive heart failure) 2
• Infants with mild cardiomyopathy not receiving medical therapy 2
• Children with Down syndrome without qualifying heart disease, chronic lung disease, airway clearance issues, or prematurity 1
• Healthy infants born at or after 29 weeks' gestation 2, 1

Dosing and Administration

• Standard dose: 15 mg/kg administered intramuscularly 3

• Maximum number of doses:

  • 5 doses for infants with hemodynamically significant CHD, CLD, or birth before 32 weeks' gestation 2, 1
  • 3 doses for qualifying infants born at 32-34 weeks' gestation, or until they reach 90 days of age, whichever comes first 1

• An additional dose should be administered post-cardiac surgery with cardiopulmonary bypass due to a 58% decrease in palivizumab serum concentration 2, 3

Clinical Efficacy

Palivizumab prophylaxis has demonstrated significant reduction in RSV-related hospitalizations:

• 55% overall reduction in hospitalization rates in high-risk infants 4
• 78% reduction in premature infants without CLD 4
• 39% reduction in children with BPD/CLD 4
• 45% reduction in children with hemodynamically significant CHD 2

Special Considerations

• Hospitalized infants who qualify for prophylaxis should receive the first dose 48-72 hours before discharge or promptly after discharge 2, 1
• If a child receiving prophylaxis is hospitalized with RSV, monthly prophylaxis should be discontinued due to the extremely low likelihood of a second RSV hospitalization in the same season 1
• Palivizumab does not interfere with response to vaccines 2, 1
• Palivizumab is not effective for treatment of established RSV disease and is not approved for this indication 2

Timing of Administration

• For most areas in the United States, initiation in November and continuation for a total of 5 monthly doses will provide protection through April 2
• If prophylaxis is initiated in October, the fifth and final dose should be administered in February 2
• Regional variations in RSV seasonality may affect timing of administration, particularly in Florida where onset can vary by region 2

Important Caveats

• Palivizumab is an expensive intervention, and cost-effectiveness must be considered when determining eligibility 2, 1
• The primary benefit is reduction in hospitalization rates, not mortality or long-term wheezing prevention 2
• Prophylaxis is not recommended for primary asthma prevention or to reduce subsequent episodes of wheezing 2
• Strict adherence to infection control practices remains essential for reducing RSV transmission 3

Palivizumab represents a significant advance in preventing serious RSV disease in high-risk infants, but its use must be carefully targeted to those most likely to benefit given its cost and the need to balance resource utilization with clinical outcomes.