The main symptoms of the flu can vary. They include a sudden high temperature of 38C or above, an aching body, a dry cough, a sore throat, and a headache.
Some people also report feeling tired or exhausted, and having difficulty sleeping.
Certain individuals also report a loss of appetite, diarrhoea or tummy pain, as well as feeling sick and being sick.
The NHS says symptoms are similar for children, but they can also get pain in their ear and appear less active.
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