Treatment of Influenza in Children
All children under 2 years with suspected or confirmed influenza should receive oseltamivir immediately, and treatment should be strongly considered for any child with severe symptoms, underlying medical conditions, or when therapy can begin within 48 hours of symptom onset. 1
Indications for Antiviral Treatment
High-Priority Groups (Treat Immediately)
- All hospitalized children with suspected influenza, regardless of vaccination status or time since symptom onset 1
- All children under 2 years of age (highest risk for complications, hospitalization, and death) 1
- Children with severe or progressive illness (respiratory distress, hypoxia, altered mental status, dehydration) 1
- Children with high-risk conditions: chronic pulmonary disease (including asthma), cardiovascular disease, renal/hepatic/metabolic disorders (including diabetes), neurologic or neurodevelopmental disorders, immunosuppression, or morbid obesity 1
Consider Treatment For
- Otherwise healthy children when treatment can start within 48 hours of symptom onset 1
- Children whose household contacts are under 6 months (cannot be vaccinated) or have high-risk medical conditions 1
Critical pitfall: Do not delay treatment while awaiting laboratory confirmation—clinical judgment based on fever, cough, and local influenza activity is sufficient to initiate therapy. 1 Rapid antigen tests have low sensitivity and should never be used to rule out influenza or withhold treatment. 1
Oseltamivir Dosing
Infants Under 12 Months
| Age | Dose | Frequency | Duration |
|---|---|---|---|
| 0-8 months (term) | 3 mg/kg | Twice daily | 5 days |
| 9-11 months | 3.5 mg/kg | Twice daily | 5 days |
For preterm infants, use postmenstrual age-based dosing: <38 weeks PMA = 1.0 mg/kg twice daily; 38-40 weeks PMA = 1.5 mg/kg twice daily; >40 weeks PMA = 3.0 mg/kg twice daily. 1 Using term-infant dosing in preterm infants can cause toxic accumulation. 1
Children 12 Months and Older (Weight-Based)
| Weight | Dose | Frequency | Duration |
|---|---|---|---|
| ≤15 kg | 30 mg (5 mL) | Twice daily | 5 days |
| >15-23 kg | 45 mg (7.5 mL) | Twice daily | 5 days |
| >23-40 kg | 60 mg (10 mL) | Twice daily | 5 days |
| >40 kg | 75 mg (12.5 mL) | Twice daily | 5 days |
Adolescents ≥13 Years
Formulation: Use the oral suspension (6 mg/mL concentration) for children who cannot swallow capsules. 1 Measure doses with a calibrated oral syringe—never use household spoons. 1
Timing and Clinical Benefits
Initiate treatment immediately upon clinical suspicion—the greatest benefit occurs when started within 48 hours of symptom onset, reducing illness duration by approximately 36 hours (26% reduction) and lowering acute otitis media risk by 34%. 1 However, high-risk children still benefit even when treatment begins after 48 hours, as oseltamivir reduces complications, hospitalization, and death. 1
Supportive Care
Fever and Symptom Management
- Antipyretics and fluids for all children 3
- Never use aspirin in children due to Reye's syndrome risk 3
- Acetaminophen or ibuprofen are appropriate antipyretic choices
Oxygen Therapy
- Administer oxygen to maintain SaO₂ >92% in children with hypoxia 3, 1
- Use nasal cannulae, head box, or face mask as appropriate 3
Hydration
- Encourage oral fluids when tolerated 3
- Provide intravenous fluids if the child cannot maintain oral intake or shows signs of dehydration 3
Antibiotics
Do not routinely prescribe antibiotics—reserve them only for documented secondary bacterial infection (persistent high fever >4-5 days, focal chest findings, severe earache, clinical deterioration). 1 If bacterial pneumonia is suspected, first-line antibiotics for children under 12 years include co-amoxiclav 5 mL of 125/31 suspension three times daily. 1
Indications for Hospital Admission
Admit children with any of the following: 3
- Respiratory distress: markedly raised respiratory rate, grunting, intercostal recession, breathlessness with chest signs
- Cyanosis or inability to maintain SaO₂ >92% despite oxygen
- Severe dehydration
- Altered consciousness or complicated/prolonged seizure
- Signs of septicemia: extreme pallor, hypotension, floppy infant
Administration and Tolerability
- Give oseltamivir with food to reduce nausea and vomiting (occur in ~5-15% of children but are usually mild and transient) 1, 4
- Complete the full 5-day course even if symptoms improve earlier—early discontinuation increases resistance risk 1
- Diarrhea may occur in infants under 1 year 1
Safety reassurance: Controlled trials and surveillance have found no credible association between oseltamivir and neuropsychiatric events. 1
Alternative Antivirals (Limited Role)
- Zanamivir (inhaled): acceptable alternative for children ≥7 years without chronic respiratory disease, but more difficult to administer 1
- Peramivir (IV): approved only for children ≥2 years with acute uncomplicated influenza 1
- Amantadine/rimantadine: contraindicated due to widespread resistance 1, 5
Renal Dose Adjustment
For children with creatinine clearance 10-30 mL/min: reduce treatment dose to 75 mg once daily (instead of twice daily) for 5 days. 4
Post-Exposure Prophylaxis
Consider prophylaxis for high-risk household contacts (infants <6 months, immunocompromised, unvaccinated high-risk children) if exposure occurred within 48 hours: 1