Symptomatic Treatment for High-Risk Patients with Suspected Influenza B
High-risk patients with suspected Influenza B should receive immediate antiviral treatment with oseltamivir (75 mg twice daily for 5 days) plus symptomatic management with ibuprofen or paracetamol for fever and myalgias, without waiting for laboratory confirmation. 1
Immediate Antiviral Therapy
Start oseltamivir immediately for all high-risk patients with suspected influenza, regardless of symptom duration or vaccination status. 1, 2
- High-risk criteria include: hospitalized patients, severe or progressive illness, chronic medical conditions (cardiac, pulmonary, renal, hepatic, diabetes), immunocompromised status, children <2 years, adults ≥65 years, pregnant women and those within 2 weeks postpartum 1, 2
- Oseltamivir 75 mg orally twice daily for 5 days is the standard treatment regimen 1, 3
- Do not delay treatment while awaiting laboratory confirmation during influenza season 1, 2
- Treatment provides mortality benefit even when initiated beyond 48 hours in high-risk patients (OR 0.21 for death within 15 days) 2
Important Caveat for Influenza B
- Oseltamivir appears somewhat less effective against Influenza B compared to Influenza A, with children showing slower fever resolution and prolonged viral shedding 2, 4
- Despite reduced efficacy, treatment is still strongly recommended for high-risk patients with Influenza B 4
- Consider baloxavir as an alternative if available, as recent data shows efficacy in high-risk Influenza B patients 5, 4
Symptomatic Management
Administer ibuprofen for fever, myalgias, and headache as first-line symptomatic therapy. 6
- Ibuprofen is specifically recommended by the British Thoracic Society for fever, myalgias, and headache in influenza patients 6
- Use the lowest effective dose for the shortest duration necessary 6
- Paracetamol is an appropriate alternative in patients with gastrointestinal or cardiovascular risk factors 6
- Never use aspirin in children <16 years due to Reye syndrome risk 6
Additional Supportive Measures
- Ensure adequate rest and fluid intake 6
- Consider short-duration topical decongestants, throat lozenges, and saline nasal drops 6
- Advise smoking cessation during illness 6
Monitoring for Complications
Instruct patients to seek immediate re-evaluation if warning signs develop. 6
- Respiratory distress or painful/difficult breathing 6
- Hemoptysis (bloody sputum) 6
- Altered mental status (somnolence, disorientation, confusion) 6
- Persistent fever for 4-5 days without improvement or clinical deterioration 6
Bacterial Superinfection Surveillance
Empirically add antibiotics if bacterial coinfection is suspected, particularly with severe initial presentation or clinical deterioration after initial improvement. 1
- Investigate bacterial coinfection in patients presenting with extensive pneumonia, respiratory failure, hypotension, or those who deteriorate despite antiviral therapy 1
- Common bacterial pathogens include S. pneumoniae, S. aureus, and H. influenzae 1
- Appropriate antibiotic choices include amoxicillin-clavulanate, cefpodoxime, cefuroxime, or respiratory fluoroquinolones 1
- Consider bacterial coinfection if no improvement occurs after 3-5 days of antiviral treatment 1
Critical Pitfalls to Avoid
- Do not withhold oseltamivir based on time since symptom onset in high-risk patients - mortality benefit persists even when treatment starts up to 96 hours after onset 2
- Do not wait for laboratory confirmation before initiating treatment - rapid tests have poor sensitivity and negative results should not exclude treatment 2
- Do not routinely prescribe antibiotics for uncomplicated influenza without evidence of bacterial coinfection - this contributes to antimicrobial resistance 1
- Do not administer corticosteroids as adjunctive therapy for influenza unless clinically indicated for other reasons 1
- Do not use amantadine or rimantadine - high resistance rates make these ineffective 1, 3