What are the clinical guidelines for preventing Respiratory Syncytial Virus (RSV) lower respiratory tract disease in neonates and infants during their first RSV season?

Guidelines for Prevention of RSV Lower Respiratory Tract Disease in Neonates and Infants

Palivizumab prophylaxis is recommended only for specific high-risk infants during their first RSV season, while nirsevimab is now recommended for all infants aged <8 months born during or entering their first RSV season. 1

Eligibility Criteria for RSV Prophylaxis

First RSV Season Recommendations

Palivizumab Eligibility:

• Infants born before 29 weeks, 0 days' gestation who are younger than 12 months at the start of RSV season 1, 2
• Infants and children <24 months with chronic lung disease (CLD) who received medical therapy (supplemental oxygen, bronchodilator, diuretic or corticosteroid therapy) within 6 months before the start of RSV season 1, 2
• Infants ≤12 months with hemodynamically significant congenital heart disease (CHD) 1, 2
• Children with neuromuscular disease or congenital airway abnormalities that compromise handling of respiratory secretions 1

Nirsevimab Eligibility (Newer Recommendation):

• All infants aged <8 months born during or entering their first RSV season 1
  • 50 mg for infants weighing <5 kg
  • 100 mg for infants weighing ≥5 kg

Second RSV Season Recommendations

• Continued palivizumab prophylaxis may be considered for preterm infants born at <32 weeks, 0 days' gestation who required at least 28 days of oxygen after birth and who continue to require supplemental oxygen, chronic corticosteroid therapy, or diuretic therapy 1
• Nirsevimab (200 mg) is recommended for infants and children aged 8–19 months who are at increased risk for severe RSV disease and entering their second RSV season 1

Dosage and Administration

Palivizumab:

• Standard dose: 15 mg/kg administered intramuscularly monthly 1, 2
• Maximum 5 doses for qualifying infants during their first RSV season 1
• Post-operative dose (15 mg/kg) should be administered after cardiac bypass or at the conclusion of extracorporeal membrane oxygenation 1, 2

Nirsevimab:

• Single dose provides season-long protection 1, 3
• Dosing based on weight:
  • <5 kg: 50 mg
  • ≥5 kg: 100 mg
  • Second season (8-19 months): 200 mg (administered as two 100 mg injections) 1

Timing of Administration

• For most areas in the continental United States, initiate prophylaxis in November and continue for a total of 5 monthly doses (for palivizumab) 1
• If prophylaxis is initiated in October, the fifth and final dose should be administered in February 1
• Nirsevimab should be administered shortly before the start of RSV season 1
• Qualifying hospitalized infants should receive the first dose 48-72 hours before discharge or promptly after discharge 1

Special Considerations

Discontinuation of Prophylaxis

• If an infant receiving monthly palivizumab prophylaxis experiences breakthrough RSV hospitalization, discontinue further prophylaxis due to extremely low likelihood (<0.5%) of a second RSV hospitalization in the same season 1

Not Recommended for Prophylaxis

• Otherwise healthy infants born at or after 29 weeks, 0 days' gestation 1
• Children with Down syndrome unless they have qualifying heart disease, CLD, airway clearance issues, or prematurity (<29 weeks) 1, 2
• Routine use in patients with cystic fibrosis, unless they have CLD or nutritional compromise 1
• Prevention of health care-associated RSV disease outbreaks 1
• Primary asthma prevention or reduction of subsequent wheezing episodes 1, 2

Safety Profile

• Nirsevimab has demonstrated a favorable safety profile across clinical trials, with most adverse events being mild to moderate in severity 3
• The incidence of adverse events was similar between nirsevimab and placebo groups, with ≥98% of events unrelated to treatment 3

Infection Control Measures

• Keep high-risk infants away from crowds and situations with exposure to infected people 1
• Restrict participation in group child care during RSV season for high-risk infants 1
• Implement strict hand hygiene practices 1
• Ensure all infants (beginning at 6 months) and their contacts receive influenza vaccine and other age-appropriate immunizations 1

Common Pitfalls to Avoid

1. Continuing prophylaxis after breakthrough RSV hospitalization
2. Administering more than 5 monthly doses of palivizumab within the continental United States
3. Using palivizumab for treatment of established RSV disease (not effective)
4. Failing to administer a post-operative dose after cardiac bypass
5. Overlooking the need for strict infection control measures in addition to immunoprophylaxis

The evolution of RSV prevention strategies now includes both palivizumab for specific high-risk populations and nirsevimab as a broader preventive option for all infants in their first RSV season, significantly improving our ability to prevent severe RSV disease in vulnerable infants.