Patient handout

Pediatric Influenza

PRODUCTION

1. Your condition

This handout is for pediatric influenza. Your care team identified this based on: pediatric influenza-like illness: acute onset fever + cough + sore throat + myalgia during influenza season (aap red book 2025-26; cdc peds 2025-26; idsa 2018 pmid 30566567).

Other reasons your team may use this plan: household or school / daycare outbreak exposure to confirmed influenza case — high-risk peds contact for pep + active surveillance (cdc peds 2025-26; aap red book 2025-26); positive rapid molecular flu / multiplex flu-covid-rsv pcr — pediatric (aap red book 2025-26; cdc peds 2025-26); pediatric respiratory failure (spo2 < 92% ra, retractions, grunting, rr ≥ 60 < 5 yr / ≥ 40 5-12 yr / ≥ 30 ≥ 12 yr) in setting of ili — admit + empiric oseltamivir + complications evaluation (aap red book 2025-26; idsa 2018 pmid 30566567; bhat nejm 2005 pmid 16354892).

2. Your medications

Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.

Medication	Starting dose	How	When	What it does
oseltamivir	Term neonate 0-1 mo + 1-12 mo: 3 mg/kg/dose PO BID × 5 d; ≥ 1 yr weight-banded: ≤ 15 kg 30 mg BID, > 15-23 kg 45 mg BID, > 23-40 kg 60 mg BID, > 40 kg 75 mg BID × 5 d; extend to 10 d if ICU or immunocompromised	PO	BID × 5 d (× 10 d if ICU/immunocompromised)	First-line peds antiviral for all ages including infants < 1 mo per AAP Red Book 2025-26 + CDC peds 2025-26; Dobson IPD meta PMID 25640810 peds subgroup demonstrates ~ 1-day symptom-duration reduction + reduced complications + reduced hospitalization in high-risk; start empirically without waiting for test results in high-risk + hospitalized + < 2 yr (independent high-risk)
baloxavir marboxil	Single dose 40 mg PO if < 80 kg or 80 mg PO if ≥ 80 kg	PO	single dose	Single-dose convenience for ≥ 5 yr healthy (FDA 2022 peds expansion) and ≥ 12 yr high-risk per CDC peds 2025-26; CAPSTONE-1 PMID 30184455 adolescent ≥ 12 yr subgroup demonstrated non-inferiority to oseltamivir + superior viral load reduction; AVOID with polyvalent cation-containing products (Ca/Mg/Fe antacids reduce absorption); not recommended in pregnancy or severely immunocompromised
peramivir	≥ 6 mo to < 13 yr: 12 mg/kg IV (max 600 mg) single dose; ≥ 13 yr: 600 mg IV single dose	IV	single dose	IV alternative when oral/enteral not feasible per CDC peds 2025-26; ≥ 6 mo FDA-approved; single dose non-inferior to 5-d oseltamivir for uncomplicated influenza
zanamivir	≥ 7 yr: 10 mg (2 inhalations × 5 mg) inhaled BID × 5 d	inhaled	BID × 5 d	Inhaled alternative ≥ 7 yr per CDC peds 2025-26; AVOID in asthma + chronic lung disease per bronchospasm risk (FDA label); rarely used in current peds practice given oseltamivir + baloxavir availability

Plan: Pediatric influenza antiviral treatment — oseltamivir age + weight-banded all ages (first-line) + baloxavir ≥ 5 yr healthy / ≥ 12 yr high-risk + peramivir IV ≥ 6 mo + zanamivir ≥ 7 yr inhaled (AVOID asthma) (AAP Red Book 2025-26; IDSA 2018 PMID 30566567; CDC peds 2025-26)

3. When to call your provider

Contact your care team if any of the following happen:

oxygen level (SpO₂) < 92% RA + retractions → admit (AAP Red Book 2025-26)
Age-specific tachypnea + WOB → admit (AAP Red Book 2025-26)
Persistent fever > 3 d → reassess for bacterial superinfection (AAP Red Book 2025-26)
Dehydration with inability to maintain PO → IV fluids + admit (AAP Red Book 2025-26)
Altered mental status / seizures → emergent evaluation + admit + neurology (Mizuguchi Brain Dev 1997 PMID 11057302)
Chest pain + arrhythmia → cardiology + ECG + troponin (Steininger Clin Infect Dis 2003)
Age < 6 mo with significant febrile illness → admit + febrile-infant pathway (AAP Red Book 2025-26)

4. When to seek emergency care

Call 911 or go to the nearest emergency room right away if you have:

Pediatric respiratory failure in influenza — oxygen level (SpO₂) < 92% RA + retractions + age-specific tachypnea (RR ≥ 60 < 5 yr / ≥ 40 5-12 yr / ≥ 30 ≥ 12 yr) → admit + HFNC 1-2 L/kg/min per PARIS PMID 29562151 + CPAP/BiPAP/intubation for failure + ARDSnet if PaO2/FiO2 ≤ 200 + prone positioning if PaO2/FiO2 < 150 per PROSEVA Guérin NEJM 2013 (AAP Red Book 2025-26)(life-threatening)
Pediatric influenza-associated neurologic disease (IAND) / acute necrotizing encephalopathy (ANE) — altered mental status + seizures + focal neurological deficits in confirmed/suspected pediatric influenza + symmetric thalamic / brainstem / cerebellar lesions on MRI (Mizuguchi pattern) → ICU + neurology + EEG + MRI + LP + CSF (rule out HSV — empiric IV acyclovir pending PCR per Tunkel IDSA encephalitis 2008) + continue oseltamivir; mortality 30-50% in severe ANE; long-term sequelae common in survivors (Mizuguchi Brain Dev 1997 PMID 11057302; AAP Red Book 2025-26)(life-threatening)
Pediatric influenza-associated myocarditis — chest pain + new ECG changes (ST changes, conduction abnormalities) + elevated troponin in confirmed/suspected influenza ± new HF features (EF drop on echo, regional wall motion abnormalities, new pulmonary edema, hemodynamic compromise) → echocardiography + cardiology consult + telemetry + standard HF therapy (guideline-directed but cautious diuresis) + continue oseltamivir + consider cardiac MRI (Steininger Clin Infect Dis 2003; AAP Red Book 2025-26)
Pediatric influenza bacterial superinfection — biphasic illness pattern (initial improvement → recurrent fever + new productive cough + new focal consolidation on CXR + leukocytosis disproportionate to influenza lymphopenia OR procalcitonin > 0.25 ng/mL) — add empiric amoxicillin/clavulanate (outpatient overlap — 80-90 mg/kg/d amoxicillin component PO BID) OR ceftriaxone IV ± vancomycin (inpatient/PICU; anti-MRSA if necrotizing pneumonia features); S. aureus including MRSA + S. pneumoniae + S. pyogenes most common; cross-route to peds.cap.v1 (Bhat NEJM 2005 PMID 16354892; IDSA 2018 PMID 30566567; IDSA/PIDS Peds CAP 2011)
Pediatric MIS-C-like post-viral hyperinflammatory syndrome — 2-6 wk post-influenza + multi-organ involvement (cardiac — myocarditis, cardiogenic shock; mucocutaneous — Kawasaki-disease-like; GI — abdominal pain, vomiting, diarrhea) + elevated inflammatory markers (CRP, ferritin, ESR, D-dimer) — ICU + cardiology + rheum + ID consult; management extrapolated from MIS-C protocols (IVIG + glucocorticoids + biologics if refractory); less common than post-COVID MIS-C but reported (Sun MMWR 2021; AAP Red Book 2025-26)
High-risk pediatric outpatient with ILI not yet on antiviral therapy: age < 5 yr (especially < 2 yr — independent high-risk) / asthma / immunocompromised / CHD / neuromuscular / sickle cell / chronic metabolic / on long-term aspirin (juvenile RA — Reye risk independent of influenza) / American Indian / Alaska Native heritage — start oseltamivir age/weight-banded immediately even if symptom onset > 48 h (AAP Red Book 2025-26; IDSA 2018 PMID 30566567; CDC peds 2025-26)
Pediatric age < 2 yr with influenza is an INDEPENDENT HIGH-RISK condition per AAP Red Book 2025-26 + CDC peds 2025-26 — start oseltamivir age/weight-banded empirically regardless of symptom-onset window; lower admission threshold for any progressive symptoms; surveillance for ANE / IAND / myocarditis / bacterial superinfection; cross-reference peds.bronchiolitis.v1 for differential in younger infants with wheeze; cross-reference peds.febrile-infant.core.v1 if < 60 d febrile (AAP Red Book 2025-26; CDC peds 2025-26)
Immunocompromised pediatric patient with influenza — risk of prolonged viral shedding, antiviral resistance emergence (H275Y NA mutation oseltamivir resistance; PA I38T baloxavir resistance), progressive viral pneumonia (IDSA 2018 PMID 30566567; AAP Red Book 2025-26)

5. Follow-up

Post-influenza pediatric follow-up: annual influenza vaccination if unvaccinated this season + next season per ACIP 2025-26 (LAIV ≥ 2 yr healthy non-pregnant non-immunocompromised non-asthma; IIV otherwise; all ≥ 6 mo); household + school contact PEP for high-risk contacts (oseltamivir age/weight-banded × 7 d for high-risk within 48 h of exposure); school return when afebrile ≥ 24 h without antipyretics per CDC public health guidance; cardiology follow-up if myocarditis (echo at 3 + 6 mo; activity restriction per ACC/AHA peds myocarditis statement); neurology + neuropsych follow-up if ANE / IAND (serial imaging + functional assessment; mortality 30-50% in severe ANE per Mizuguchi 1997 PMID 11057302; long-term sequelae common); ID follow-up if immunocompromised; rheum + cardiology if MIS-C-like; public health reporting if institutional outbreak; aspirin reconciliation if held for Reye risk (AAP Red Book 2025-26; CDC peds 2025-26; ACIP 2025-26)

6. Sources

Guideline: AAP Red Book 2025-26 — Influenza chapter (pediatric) + IDSA 2018 Clinical Practice Guidelines for Seasonal Influenza (Uyeki Clin Infect Dis 2019) + CDC Pediatric Antiviral Guidance 2025-26 Season