Flu 

Introduction 

Cold or flu?

Do you know the difference between a cold and flu? An expert explains the conditions, treatments and remedies available.

Is it seasonal flu or swine flu?

Swine flu, also called H1N1 flu, is a relatively new strain of flu. It was one of the main flu viruses circulating last winter and was therefore included in the annual flu jab.

It can be difficult to tell the difference between seasonal flu and swine flu. They both have similar symptoms (fever, cough, sore throat, aching muscles) and are caught and spread in the same way.

Read more about swine flu.

Help fight flu

Sign up for the flu survey to help researchers at the London School of Hygiene and Tropical Medicine track the spread of flu and discover more about it. The survey takes just a few minutes each week and anyone can take part.

Flu is a highly infectious and very common viral illness that is spread by coughs and sneezes.

It's not the same as the common cold. Flu is caused by a different group of viruses and symptoms tend to be more severe and last for longer.

You can catch flu – short for influenza – all year round, but it is especially common in winter, which is why it is also known as 'seasonal flu'.

Flu causes a sudden high temperature, headache and general aches and pains, tiredness and sore throat.

You can also lose your appetite, feel nauseous and have a cough.

Flu symptoms can make you feel so exhausted and unwell that you have to stay in bed and rest until you feel better.

Read more about the symptoms of flu.

When to see a doctor

If you are otherwise fit and healthy, there is usually no need to see a doctor if you have flu-like symptoms. 

The best remedy is to rest at home, keep warm and drink plenty of water to avoid dehydration.

You can take paracetamol or ibuprofen,  to lower a high temperature and relieve aches.

You should see a doctor if you have flu-like symptoms and you:

  • are 65 or over
  • are pregnant
  • have a long-term medical condition such as diabetes, heart disease, lung disease, kidney or neurological disease
  • have a weakened immune system

This is because flu can be more serious for you, and your doctor may want to prescribe antiviral medication.

Antiviral medicine can lessen the symptoms of flu and shorten its duration, but treatment needs to start soon after flu symptoms have begun in order to be effective.

Antibiotics are of no use in the treatment of flu because it is caused by a virus and not bacteria.

Read more about how to treat flu and who should see a doctor.

How long does flu last?

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

Symptoms peak after two to three days and you should begin to feel much better after a week or so, although you may feel tired for much longer.

You are usually infectious – that is able to pass on flu to others – a day before your symptoms start, and for a further five or six days. Children and people with weaker immune systems, such as cancer patients, may remain infectious for longer.

Elderly people and anyone with certain long-term medical conditions are more likely to have a bad case of flu, and are also more likely to develop a serious complication such as a chest infection.

In the UK, about 600 people a year die from a complication of seasonal flu. This rises to around 13,000 during an epidemic.

Read more about the complications of flu.

Preventing the spread of flu

The flu virus is spread in the small droplets of fluid coughed or sneezed into the air by an infected person. These droplets can travel a metre or so and infect anyone within range who breathes them in.

Flu can also spread if someone with the virus transfers it on their fingers. For example, if you have flu and you touch your nose or eyes and then touch someone else, you may pass the virus on to them. Similarly if you have flu and touch common hard surfaces such as door handles with unwashed hands then other people who touch the surface after you can pick up the infection.

Read more about the causes of flu.

You can stop yourself catching flu in the first place or spreading it to others by being careful with your hygiene. 

Always wash your hands regularly with soap and water and:

  • regularly clean surfaces such as your keyboard, telephone and door handles to get rid of germs
  • use tissues to cover your mouth and nose when you cough or sneeze
  • put used tissues in a bin as soon as possible

Learn more about stopping the spread of flu by watching this video about the government's Catch it, Bin it, Kill it campaign.

You can also help stop the spread of flu if you avoid all unnecessary contact with other people while you're infectious. You should stay off work until you are no longer infectious and you are feeling better.

Read more about how to stop the spread of flu.

The flu jab

A flu vaccine is available free on the NHS if you:

  • are pregnant
  • 65 or older
  • have a serious medical condition
  • are a healthcare worker or carer
  • live in a residential or nursing home

Despite popular belief, the flu vaccine cannot give you flu as it doesn't contain the active virus needed to do this.

The flu vaccine is available from October each year. If you think you need it, talk to your GP or practice nurse.

For more information on who should have the flu jab and how to get it read our section on the seasonal flu jab.

  • show glossary terms
Epidemic
An epidemic is a sudden outbreak of disease that spreads through a population in a short amount of time.
Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.

Last reviewed: 11/08/2011

Next review due: 11/08/2013

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Comments are personal views. Any information they give has not been checked and may not be accurate.

Mikegall said on 07 August 2011

The description of the flu is quite accurate. I wonder about the efficacy of the flu jab?

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AquaBabe said on 28 February 2011

A friend of mine had the seasonal flu jab last November but has been in bed for nearly a week with a bad dose of flu. Her GP confirmed today that it is the flu.

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