Influenza pandemic: what to know

A pandemic occurs when a new influenza virus spreads across countries and many people have limited prior immunity. It is different from a seasonal influenza wave, although both can cause fever, cough, chills, headache, fatigue and feeling generally unwell.

Public-health guidance may change as officials learn about transmission, severity and which groups are most vulnerable. Pneumonia is one possible serious complication of influenza. A pandemic label describes the spread of a virus; it does not predict how severe every individual illness will be.

Use current advice from local health authorities, stay home when sick, ventilate shared spaces, wash hands and cover coughs. Keep a plan for medicines, fluids and contact with a healthcare service. Protect people at higher risk by avoiding close contact while symptomatic and following guidance on vaccination, masks, testing or gatherings.

Contact a clinician promptly if you are in a higher-risk group or symptoms are worsening. Seek urgent help for breathlessness, chest pain, confusion, fainting, severe dehydration, blue or grey lips, or marked weakness. Do not delay emergency care because a public-health announcement is still being updated.

Ask which local instructions apply, whether you need testing or treatment, and how to protect household members. Share your symptom start date, travel or exposure information, pregnancy status, long-term conditions and medicines.