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Flu symptoms

What is the Flu?

Flu is a common illness, caused by a virus and easily spread by coughs and sneezes. It can be very unpleasant, but most people begin to feel better within about a week.You can catch flu – also known as influenza – all year round, but it's especially common in the winter season, which is why it's sometimes called "seasonal flu".It's not the same as the common cold. Flu is caused by a different group of viruses and the symptoms tend to start more suddenly, be more severe and last longer.  Flu can be very serious for some people.

Some of the main symptoms of flu include:

  • a high temperature (fever) of 38C (100.4F) or above
  • tiredness and weakness
  • a headache
  • general aches and pains
  • a dry, chesty cough

A blocked or runny nose, sneezing, and a sore throat – can also be caused by flu.

Flu can make you feel so exhausted and unwell that you have to stay in bed and rest until you feel better. Some people are more at risk to complications if they get flu than others, this includes the very young, the elderly, pregnant women and those with long term health conditions. 

How long does flu last and is it serious?

If you have flu, you generally start to feel ill within a few days of being infected.

You will probably begin to feel much better within a week or so.

You will usually be most infectious from the day your symptoms start and for a further three to seven days. Children and people with weaker immune systems may remain infectious for longer. Some people are infectious and have no symptoms.

Most people will make a full recovery and won't experience any further problems, but elderly people, the very young, pregnant women and people with certain long-term medical conditions are more likely to have a bad case of flu or develop a serious complication, such as a chest infection.

Some people are infected with flu and have no symptoms, but they can still pass it on.

Read more about the complications of flu.