What is the recommended treatment for a patient co-infected with COVID-19 and influenza (flu)?

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Last updated: January 21, 2026View editorial policy

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Treatment for COVID-19 and Influenza Co-infection

For patients co-infected with COVID-19 and influenza, treat both infections concurrently with oseltamivir or baloxavir for influenza according to standard guidelines, while continuing COVID-19 specific therapies without modification. 1

Diagnostic Approach

  • Confirm influenza coinfection using PCR or rapid testing of nasopharyngeal secretions when clinically suspected in any COVID-19 positive patient, as documented coinfection rates range from 0.5-2%. 1
  • Obtain comprehensive microbiologic workup including blood cultures, sputum cultures, and pneumococcal urinary antigen testing before initiating any empirical antibiotics. 2
  • Direct PCR testing of nasopharyngeal or respiratory secretions is recommended for both pathogens. 2

Antiviral Treatment Strategy

For Influenza Component

  • Administer oseltamivir or baloxavir immediately upon confirmation of influenza coinfection, following standard influenza treatment guidelines. 2, 1
  • Continue influenza antiviral therapy for the full treatment course regardless of COVID-19 status. 1

For COVID-19 Component

  • Non-hospitalized or mild cases: Provide supportive care including rest, nutrition, and fluid support; no immunomodulatory therapy is indicated. 3
  • Hospitalized patients requiring supplemental oxygen: Administer systemic corticosteroids, preferably dexamethasone, as this decreases mortality. 2, 3
  • Hospitalized patients requiring oxygen, non-invasive ventilation, or mechanical ventilation: Consider combination therapy with glucocorticoids plus tocilizumab, as this reduces disease progression and mortality. 2, 3
  • Hospitalized patients requiring oxygen therapy or high-flow oxygen: The combination of glucocorticoids with baricitinib or tofacitinib could be considered as it might decrease disease progression and mortality. 2

Antibiotic Considerations

Do not routinely prescribe antibiotics for COVID-19/influenza coinfection. 2 However, specific circumstances warrant consideration:

  • Consider empirical antibiotics only if bacterial superinfection cannot be ruled out, as bacterial coinfection occurs in approximately 40% of viral respiratory infections requiring hospitalization. 1
  • Bacterial coinfection upon admission occurs in only 3.5% of COVID-19 patients, while secondary bacterial infections during hospitalization occur in up to 15%. 2
  • If antibiotics are initiated empirically, stop antibiotics after 48 hours if representative cultures and urinary antigen tests show no bacterial pathogen involvement. 2
  • For confirmed secondary bacterial respiratory infection, follow guideline recommendations for hospital-acquired and ventilator-associated pneumonia treatment. 2
  • Limit antibiotic treatment duration to 5 days in patients with suspected bacterial respiratory infection upon improvement of signs, symptoms, and inflammatory markers. 2

Critical Management Pitfalls

  • Avoid hydroxychloroquine at any stage of SARS-CoV-2 infection, as it provides no additional benefit and could worsen prognosis, particularly if co-prescribed with azithromycin. 2
  • Do not withhold or modify immunosuppressive therapy dosing during influenza prophylaxis if the patient is on bispecific antibodies or other immunomodulatory treatments. 2, 1
  • Monitor for drug interactions carefully, particularly in patients on multiple medications for both infections. 1

Isolation and Prevention

  • Follow standard isolation protocols for both infections until clinical resolution with RT-PCR clearance. 2, 1
  • Influenza vaccination is strongly recommended for all COVID-19 patients and their close contacts to reduce coinfection risk. 2, 1
  • A two-dose series of high-dose influenza vaccine, at least one month apart, may increase likelihood of seroprotection in immunocompromised patients. 2

Symptomatic Management

  • Use paracetamol (acetaminophen) as the preferred agent for fever management rather than NSAIDs until more evidence is available. 1
  • Provide respiratory support including oxygen therapy, high-flow nasal cannula, or mechanical ventilation based on severity. 3, 4

References

Guideline

Management of Influenza in COVID-19 Positive Patients

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

COVID-19 Management Guidelines

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Treatment options for patients with severe COVID-19.

Global health & medicine, 2023

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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