Clinical practice guidelines for influenza

Key points

• For non-severe influenza at high risk of progression to severe disease, WHO suggests baloxavir (conditional recommendation, low-quality evidence), given as early as possible and within 2 days of symptom onset.
• For non-severe influenza at low risk of progression, WHO suggests not giving baloxavir.
• WHO recommends not giving oseltamivir for non-severe seasonal influenza (strong recommendation, moderate-quality evidence), a change from its earlier advice for high-risk patients.
• Favipiravir and zanamivir are not recommended for non-severe influenza (strong recommendations); laninamivir, peramivir and umifenovir are not suggested (conditional recommendations).
• Antibiotics are not recommended in non-severe influenza with a low probability of bacterial co-infection.

Overview

The 2024 WHO clinical practice guidelines for influenza give GRADE-based recommendations on antiviral and other treatment. This summary covers mainly the recommendations for patients with suspected or confirmed non-severe influenza; the guideline also contains separate recommendations for severe disease and prophylaxis. Decisions were driven by the likelihood of progression to severe influenza and by patient values and preferences.

Who is at high risk

Patients with non-severe influenza at high risk of severe disease include those aged 65 years and older and those with one or more major risk factors for severe influenza. Patients with zoonotic influenza associated with high mortality, such as HPAI A(H5N1), HPAI A(H5N6) and HPAI and LPAI A(H7N9), were not in the trials, but the panel agreed the evidence would apply indirectly if they present early with mild symptoms.

Baloxavir

Baloxavir is given orally as a single weight-based dose. In high-risk patients it probably shortens time to symptom alleviation (estimated 1.02 days) and may reduce hospital admission (estimated 16 per 1000, just above the panel threshold of 15 per 1000), with little or no effect on mortality and no increase in treatment-related adverse events; it may increase the emergence of antiviral resistance. In low-risk patients there is high-certainty evidence that it does not reduce hospitalization, hence the recommendation against. Baloxavir should not be given to pregnant or postpartum women until more safety evidence is available, use in immunocompromised patients is cautioned because of resistance risk, and data are limited for children aged 5 years and younger.

Other antivirals and antibiotics

Oseltamivir has no important effect on symptom duration, hospitalization or mortality in non-severe influenza and probably increases adverse events; the recommendation is based on 22 randomized trials with 14 718 patients. Inhaled laninamivir and zanamivir carry a risk of bronchospasm in chronic pulmonary disease, and peramivir requires intravenous access. Antibiotics are strongly not recommended for patients with a below 20% risk of bacterial infection, because of adverse effects and the risk of antimicrobial resistance.

Frequently asked questions

Should healthy adults with mild flu take oseltamivir?

No. WHO recommends not giving oseltamivir for non-severe seasonal influenza, because it has no important effect on symptoms, hospitalization or death.

Who may benefit from baloxavir?

Patients with non-severe influenza at high risk of severe disease, such as people aged 65 or older or with major risk factors, treated within 2 days of symptom onset.

Are antibiotics useful for flu?

Not when bacterial co-infection is unlikely; WHO recommends against them in that situation.

Source

World Health Organization. Clinical practice guidelines for influenza. Geneva: World Health Organization; 2024. Licence CC BY-NC-SA 3.0 IGO. This summary was prepared by Medpresso from the original publication and is not a substitute for the full text or for medical advice.