Flu (influenza) is a common infectious viral illness. You can catch flu all year round, but it’s especially common in winter. This is why it’s also known as seasonal flu.
You can catch flu many times because flu viruses change regularly. Your body won’t have a natural resistance to the new versions.
Some of the main symptoms of flu include:
- a sudden high temperature
- tiredness and weakness
- a headache
- general aches and pains
- a dry, chesty cough
- sore throat
- difficulty sleeping
- loss of appetite
- diarrhoea or tummy pain
- feeling sick and being sick
- a runny or blocked nose
The symptoms are similar for children. They may also get pain in their ear and be less active.
How long do symptoms last
The symptoms of flu usually develop 1 to 3 days after becoming infected. Most people will feel better within a week.
But, you may have a lingering cough and still feel very tired for a few more weeks.