Influenza (Seasonal Flu)

Influenza, commonly called the flu, is a contagious respiratory illness caused by influenza viruses. It tends to be more sudden in onset and more severe than the common cold, and can lead to serious complications, particularly in young children, older adults, pregnant women, and people with chronic illness.

• Sudden onset of fever and chills
• Muscle or body aches
• Fatigue, which can be pronounced
• Headache
• Cough, sore throat, and runny or stuffy nose
• Some people, especially children, may also have vomiting or diarrhoea

• Caused by influenza viruses, which circulate seasonally and change slightly from year to year.
• Spread mainly through respiratory droplets when an infected person coughs, sneezes, or talks, and by touching contaminated surfaces.
• People are typically contagious from about a day before symptoms start until roughly a week afterward.

• Usually diagnosed clinically based on the sudden onset of fever with body aches, fatigue, and respiratory symptoms, particularly during a local flu season or outbreak.
• Rapid influenza testing, where available, can confirm the diagnosis, which may be useful for guiding antiviral treatment decisions in higher-risk patients or for surveillance purposes.

Most healthy people recover with supportive care alone — rest, adequate fluids, and paracetamol or ibuprofen for fever and aches.

Antiviral medicine (such as oseltamivir), started within the first couple of days of symptoms, may be considered for people at higher risk of complications, such as young children, older adults, pregnant women, or those with chronic health conditions.

Antibiotics are not effective against influenza itself but may be needed if a secondary bacterial infection, such as bacterial pneumonia, develops as a complication.

Medical care should be sought urgently for difficulty breathing, chest pain, persistent high fever, confusion, or symptoms that improve and then suddenly worsen, as these can indicate a serious complication.

• Get an annual influenza vaccination, particularly important for young children, older adults, pregnant women, and people with chronic illness.
• Wash hands frequently and avoid close contact with people who are sick.
• Cover coughs and sneezes, and stay home when unwell to avoid spreading the virus to others.
• Clean frequently touched surfaces regularly, especially during flu season.