NICE guidance - the use of oseltamivir , zanamivir and amantadine for the prophylaxis of influenza

NICE Guidance on antiviral post-exposure prophylaxis of influenza

• post-exposure prophylaxis (PEP) with oseltamivir or zanamivir is recommended within marketing authorizations for at-risk individuals during periods of circulating influenza (1, 2)
• updated UK Health Security Agency (UKHSA) guidance expands eligibility, allowing PEP to be offered to severely immunosuppressed individuals regardless of seasonal influenza vaccination status (2)
• PEP should be initiated as early as possible following close exposure (within 48 hours for oseltamivir and within 36 hours for inhaled zanamivir) (1)

Indications and Prescribing Criteria

Primary Care Thresholds

• offer PEP to exposed individuals during the circulating influenza season if all of the following criteria apply (1, 2):
  • national surveillance schemes indicate influenza virus is circulating in the community (1)
  • the individual has had close contact with a person with suspected or confirmed influenza-like illness (e.g., household or long-term residential setting contact) (1)
  • the individual falls into an at-risk clinical group or is severely immunosuppressed (1, 2)
  • prophylaxis can be initiated within the licensed timeframe (48 hours for oseltamivir; 36 hours for zanamivir) (1)

Vaccination Status Considerations

• standard at-risk groups: historically restricted to individuals not effectively protected by vaccination (unvaccinated, vaccine failure, or strain mismatch) (1)
• severely immunosuppressed individuals: UKHSA guidance removes the non-vaccination requirement, recommending PEP following exposure regardless of vaccination history due to impaired immune response (2)

Clinical Risk Groups

• adults aged 65 years or older (1)
• chronic respiratory disease (including severe asthma requiring continuous or frequent systemic steroids) (1)
• chronic heart, renal, hepatic, or neurological disease (1)
• diabetes mellitus (1)
• morbid obesity (BMI >= 40 kg/m2) (2)
• pregnancy (including up to 2 weeks post-partum) (2)
• immunosuppression (including severe primary immunodeficiencies, active chemotherapy/radiotherapy, organ transplant recipients, high-dose systemic steroids, and advanced HIV) (1, 2)

Outbreak Control and Choice of Agent

Localised Institutional Outbreaks

• during localized outbreaks in long-term care or nursing homes (even outside periods of general community circulation), PEP may be used for at-risk residents regardless of vaccination status once influenza is virologically confirmed in index cases (1, 2)

Antiviral Selection and Non-Recommended Agents

• selection between oseltamivir and zanamivir should consider patient delivery preferences, contraindications, and potential adverse effects (1)
• seasonal (continuous) prophylaxis is not routinely recommended in community primary care (1)
• amantadine is not recommended for influenza prophylaxis or treatment (1)

Reference:

1. National Institute for Health and Care Excellence (NICE). Oseltamivir, amantadine and zanamivir for the prophylaxis of influenza. NICE Technology Appraisal [TA158]. 2008 (reviewed 2014).
2. 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.