Flu

Flu carries an increased risk of complications and serious illness for older people (aged 65 and over), and people with long-term medical conditions.
Having the flu is more severe than a when you have a cold, and symptoms often develop more quickly. The symptoms of the flu include:
a fever that comes on quickly
severe aches and pains,
exhaustion, and
having difficulty sleeping.
While recovery from the common cold usually occurs within a week, the severe stage of flu usually lasts 3 - 5 days. It can then be followed by up to three weeks of post-viral fatigue (tiredness). If your symptoms persist for longer than a week or become very severe, see your GP.
Older people and those with long-term medical conditions may need medical attention earlier.