What is the appropriate treatment for a 5‑month‑old infant with respiratory syncytial virus infection?

Treatment of RSV in a 5-Month-Old Infant

Treatment for RSV infection in a 5-month-old is purely supportive care—there is no effective antiviral therapy for routine use in otherwise healthy infants. 1, 2

Core Supportive Management

The cornerstone of RSV treatment at this age consists of:

• Hydration support: Ensure adequate fluid intake through oral feeding, or provide nasogastric/intravenous fluids if the infant cannot maintain oral intake 1, 3
• Oxygen supplementation: Administer supplemental oxygen if saturation falls persistently below 90% 1, 3
• Fever management: Use acetaminophen for fever or discomfort as needed 1, 3
• Nasal saline irrigation: May provide symptomatic relief for upper respiratory congestion 1, 2

What NOT to Use

Critical pitfall: Palivizumab has no therapeutic benefit for treating established RSV infection—it is only approved for prevention in high-risk infants and should never be used as treatment. 1, 3, 2

Additional therapies to avoid in routine cases:

• No routine antibiotics: Only use if specific bacterial co-infection is suspected (clinical deterioration after 48-72 hours, elevated inflammatory markers, or specific radiographic findings) 1, 3
• No corticosteroids: Not recommended for routine bronchiolitis management 1
• No ribavirin: Reserved exclusively for severely immunocompromised patients (hematopoietic stem cell transplant recipients, profound lymphopenia), not for otherwise healthy infants 1, 2, 4

Hospitalization Decision

Admit the infant if any of the following are present:

• Hypoxemia (SpO₂ persistently <90%) 1, 2
• Severe respiratory distress (significant retractions, grunting, nasal flaring) 1, 2
• Inability to maintain adequate oral intake 1, 2
• Age under 3 months (highest risk for severe disease) 3, 2
• Underlying high-risk conditions (prematurity, chronic lung disease, congenital heart disease, immunocompromise) 1, 2

Monitoring During Illness

For hospitalized infants:

• Monitor oxygen saturation at least every 4 hours 3
• Assess work of breathing, respiratory rate, and mental status regularly 1, 3
• Provide IV fluids at 80% of baseline maintenance if needed, with electrolyte monitoring 3
• Expect clinical improvement within 48-72 hours with adequate supportive care 3

Discharge Readiness

The infant can be discharged when ALL of the following criteria are met:

• Oxygen saturation consistently >90% in room air for at least 12-24 hours 1, 3, 2
• Absence of substantially increased work of breathing, sustained tachypnea, or tachycardia 1, 3
• Ability to maintain adequate oral intake 1, 3
• Normal or baseline mental status 1, 3

Infection Control at Home

• Hand hygiene: The single most important measure to prevent transmission to others 1, 2
• Keep the infant away from crowds and sick contacts 1
• Avoid all tobacco smoke exposure 5, 1
• Continue breastfeeding if applicable (may decrease risk of severe disease) 5, 1

Red Flags for Return to Emergency Department

Instruct caregivers to return immediately if:

• Oxygen saturation falls below 90% 1
• Increased work of breathing (visible chest retractions, flaring nostrils, grunting) 1
• Rapid breathing that doesn't improve with rest 1
• Lethargy, difficulty waking, or altered mental status 1
• Inability to feed or signs of dehydration 1

Special Consideration: Prevention for Future Seasons

While not applicable for current treatment, note that this 5-month-old would not typically qualify for palivizumab prophylaxis unless born ≤28 weeks gestation, has chronic lung disease requiring treatment, or has hemodynamically significant congenital heart disease. 5, 1, 2 Newer prevention with nirsevimab (long-acting monoclonal antibody) is now recommended for all infants <8 months entering their first RSV season. 1, 2