NICE guidance - zanamivir for influenza

Zanamivir (inhaled neuraminidase inhibitor) is recommended within its marketing authorisation for both the treatment and post-exposure prophylaxis (PEP) of seasonal influenza in at-risk individuals during periods of community circulation (1, 2, 3):

• updated UK Health Security Agency (UKHSA) guidance aligns with international WHO/ECDC terminology, replacing "complicated / uncomplicated" with "severe / non-severe" influenza (3)
• antiviral therapy acts as an adjunct to, and not a substitute for, seasonal influenza vaccination (1, 2)

Indications and Prescribing Criteria

Treatment Criteria (TA168 Framework)

• offer zanamivir for acute non-severe influenza treatment if all of the following apply (1, 3):
  • national surveillance confirms seasonal influenza virus is circulating in the community (1)
  • the individual is in an at-risk clinical group or is severely immunosuppressed (1, 3)
  • treatment can be initiated within licensed windows of symptom onset (within 48 hours for adults; within 36 hours for children aged 5 years and over) (1)

Post-Exposure Prophylaxis Criteria (TA158 Framework)

• offer zanamivir for PEP following close contact with a suspected or confirmed index case if all of the following apply (2, 3):
  • national surveillance confirms influenza is circulating in the community (2)
  • the individual is in an at-risk clinical group or is severely immunosuppressed (2, 3)
  • prophylaxis can be initiated within 36 hours of last contact (2)
  • note: severely immunosuppressed individuals may receive PEP regardless of seasonal influenza vaccination status (3)

Clinical Risk Groups

• adults aged 65 years or older (1, 2)
• chronic respiratory disease (including asthma and COPD) (1, 2)
• chronic cardiac, renal, hepatic, or neurological conditions (1, 2)
• diabetes mellitus (1, 2)
• morbid obesity (BMI >= 40 kg/m2) (3)
• pregnancy (including up to 2 weeks post-partum) (3)
• immunosuppression (1, 2, 3)

Zanamivir Prescribing Considerations

Dosing and Administration

• treatment dose: 10 mg (2 inhalations) twice daily for 5 days in adults and children aged 5 years and over (1, 3)
• prophylaxis dose: 10 mg (2 inhalations) once daily for 10 days in adults and children aged 5 years and over (2, 3)

Clinical Positioning and Precautions

• alternative first-line role: preferred option where oseltamivir is unsuitable, poorly tolerated, or where oseltamivir resistance is suspected (3)
• respiratory caution: avoid inhaled zanamivir in patients with severe asthma or severe COPD due to the risk of acute bronchospasm (3)
• non-recommended agents: amantadine is not recommended for the treatment or prophylaxis of influenza (1, 2)

Reference:

1. National Institute for Health and Care Excellence (NICE). Amantadine, oseltamivir and zanamivir for the treatment of influenza. NICE Technology Appraisal [TA168]. 2009.
2. National Institute for Health and Care Excellence (NICE). Oseltamivir, amantadine and zanamivir for the prophylaxis of influenza. NICE Technology Appraisal [TA158]. 2008 (reviewed 2014).
3. UK Health Security Agency (UKHSA). Guidance on use of antiviral agents for the treatment and prophylaxis of seasonal influenza. UKHSA Public Health Guidance. Updated October 2026.