What are the recommendations for managing influenza?

Influenza Management Guidelines

Antiviral treatment should be offered as early as possible to hospitalized patients with suspected or confirmed influenza, patients with severe/complicated disease, and those at high risk of complications, regardless of influenza vaccination status. 1

Diagnostic Approach

• Diagnosis is primarily clinical in outpatient settings, with laboratory confirmation recommended for hospitalized patients or when confirmation would change management decisions 2
• Preferred diagnostic tests include rapid molecular assays (nucleic acid amplification tests) over rapid influenza diagnostic tests (RIDTs) due to improved sensitivity 2
• Nasopharyngeal specimens (optimal) or mid-turbinate nasal swabs should be collected for better detection 2
• For patients on mechanical ventilation, endotracheal aspirate or bronchoalveolar lavage fluid specimens are recommended 2

Treatment Recommendations

Indications for Antiviral Treatment

• Immediate treatment (regardless of symptom duration) for:

  • Any hospitalized patient with suspected or confirmed influenza 1, 2
  • Patients with severe, complicated, or progressive illness 1
  • Patients at high risk of complications (including children <2 years, adults ≥65 years, pregnant women, immunocompromised individuals, and those with chronic medical conditions) 1, 3

• Consider treatment for:

  • Otherwise healthy patients with uncomplicated influenza if treatment can be initiated within 48 hours of symptom onset 1
  • Patients whose household contacts are at high risk (e.g., children <6 months, immunocompromised individuals) 1, 4

Antiviral Medication Options

First-line Treatment: Oseltamivir (Tamiflu)

• Adult dosing: 75 mg twice daily for 5 days 5
• Pediatric dosing (based on weight): 1, 5
  • ≤15 kg: 30 mg twice daily
  • 15.1-23 kg: 45 mg twice daily
  • 23.1-40 kg: 60 mg twice daily

  • 40 kg: 75 mg twice daily

• Children <1 year: 3 mg/kg/dose twice daily 1
• Renal adjustment: Reduce dose by 50% if creatinine clearance <30 mL/min 1
• Common side effect: Nausea (10% of patients), which can be managed with mild anti-emetics 1

Alternative Options

• Zanamivir (Relenza): 10 mg (two 5-mg inhalations) twice daily for 5 days for patients ≥7 years; not recommended for patients with underlying respiratory disease 1
• Baloxavir (Xofluza): Single-dose treatment for patients ≥12 years; alternative when compliance is a concern 1

Timing of Treatment

• Optimal timing: Within 48 hours of symptom onset, with greatest benefit when started within 24 hours 1, 6
• Late treatment: Still beneficial for hospitalized patients, those with severe disease, or high-risk patients even if beyond 48 hours 1, 3

Chemoprophylaxis Recommendations

Antiviral chemoprophylaxis with oseltamivir is recommended for: 1

• Children at high risk of complications for whom influenza vaccine is contraindicated
• Children at high risk during the 2 weeks after influenza vaccination, before optimal immunity is achieved
• Unvaccinated family members or healthcare personnel with likely ongoing exposure to unvaccinated high-risk children or infants <24 months
• Control of influenza outbreaks in closed institutional settings with high-risk children
• Supplement to immunization for high-risk children, including immunocompromised patients who may not respond to vaccine

Prophylaxis dosing: Same weight-based dosing as treatment but administered once daily for 10 days 1, 5

Clinical Benefits of Antiviral Treatment

• Reduces duration of illness by approximately 24 hours in otherwise healthy patients 1, 7
• Decreases severity of symptoms by up to 38% when initiated early 7
• Reduces risk of complications including pneumonia (by 50%) and otitis media in children (by 34%) 3
• May reduce hospitalization rates and mortality in high-risk patients 1, 3
• Decreases subsequent antibiotic use 1, 7

Prevention Strategies

• Annual influenza vaccination remains the cornerstone of prevention for all individuals ≥6 months of age 1, 2
• Vaccination is especially important for healthcare personnel to reduce healthcare-associated influenza infections 1
• Pregnant women should receive influenza vaccine at any time during pregnancy to protect themselves and their infants 1
• Children with egg allergy can receive influenza vaccine without any additional precautions 1

Special Considerations

• Pediatric patients: Children <2 years are at increased risk of hospitalization and complications from influenza 1
• Pregnant women: Should receive treatment promptly if influenza is suspected; oseltamivir is the preferred agent 1
• Immunocompromised patients: May require longer treatment courses and should receive treatment regardless of symptom duration 3, 2
• Elderly patients: May not mount adequate febrile responses; consider treatment despite atypical presentation 3