Worldwide, annual flu epidemics are estimated to result in 3 to 5 million cases of severe illness and about 250,000 to 500,000 deaths.

Influenza is an unpleasant but typically self-limiting illness, with recovery in otherwise healthy individuals usually occuring within 2-7 days. However, it can lead to severe illness in high-risk groups.

Complications may include:

• Bronchitis
• Secondary bacterial pneumonia
• Otitus media (more commonly in children)
• Meningitis
• Encephalitis
• Meningoencephalitis

People at higher risk of complicatison include:

• Children under 6 months
• Older adults
• Pregnant women
• Individuals with weakened immunie systems
• Those with underlying conditions e.g. heart or lung disease