Management of Suspected or Confirmed Influenza During Flu Season

Diagnostic Testing

RT-PCR or other molecular assays are preferred for diagnosing influenza in hospitalized patients due to their superior sensitivity 3, 4
Multiplex RT-PCR assays targeting a panel of respiratory pathogens should be used in immunocompromised patients 2
Rapid influenza diagnostic tests (RIDTs) and immunofluorescence assays should not be used in hospitalized patients except when molecular assays are unavailable, and negative results should be confirmed with RT-PCR 3
Viral culture should not be used for initial diagnosis as results are not available in time to inform clinical management 3

The Infectious Diseases Society of America recommends initiating antiviral treatment as soon as possible for hospitalized patients with influenza, outpatients with severe or progressive illness, high-risk patients, children younger than 2 years, adults ≥65 years, and pregnant women 1, 2, 5
Consider antiviral treatment for previously healthy outpatients with suspected or confirmed influenza if they can be treated within 48 hours of symptom onset 1, 5
Start treatment with a single neuraminidase inhibitor (NAI): oral oseltamivir, inhaled zanamivir, or intravenous peramivir 1, 5
For most patients, use standard FDA-approved doses rather than higher doses 1
For uncomplicated influenza in otherwise healthy ambulatory patients, oseltamivir dosage is 75 mg orally twice daily for 5 days (adults) 1
Consider longer duration of antiviral treatment for immunocompromised patients or those hospitalized with severe lower respiratory tract disease 1, 5

Investigate and empirically treat bacterial coinfection in patients with severe initial presentation, clinical deterioration after initial improvement, or failure to improve after 3-5 days of antiviral treatment 1, 6
For non-severe influenza-related pneumonia, most patients can be treated with oral antibiotics, with preferred choices being co-amoxiclav or a tetracycline 7
For severe influenza-related pneumonia, use parenteral antibiotics immediately after diagnosis, with a preferred regimen being intravenous combination of broad-spectrum β-lactamase stable antibiotic (co-amoxiclav or cephalosporin) plus a macrolide 7

Avoid corticosteroid adjunctive therapy for treatment of influenza unless clinically indicated for other reasons 1, 6, 5
Do not routinely administer immunoglobulin preparations for treatment of seasonal influenza 6
Monitor for antiviral resistance, especially in high-risk situations such as patients who develop influenza while on or immediately after NAI chemoprophylaxis, immunocompromised patients with persistent viral replication despite treatment, or patients with severe influenza who don't improve with treatment 6, 2

Consider follow-up clinical review for patients who experienced significant complications or worsening of underlying disease 7
At discharge or follow-up, provide patients with information about their illness, take-home medications, and follow-up arrangements 7