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Flu, seasonal


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

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:

  • are pregnant
  • over 65
  • 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 see Seasonal flu jab.

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 in the winter of 2009/10 and therefore included in the annual seasonal 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. 

Children to be offered annual flu vaccine

The Joint Committee on Vaccination and Immunisation (JCVI) has recommended that all children from age 2 to 17 should have the annual influenza vaccination.

The vaccine, which will be given as a nasal spray rather than an injection, is unlikely to be offered to children before 2014.

Further reading: JCVI. Position statement on the annual influenza vaccination programme (PDF, 151K). Published online July 25 2012. 

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Flu can give you any of these symptoms

  • sudden fever (a temperature of 38°C/100.4°F or above),
  • dry, chesty cough
  • headache
  • tiredness
  • chills
  • aching muscles
  • limb or joint pain
  • diarrhoea or stomach upset
  • sore throat
  • runny or blocked nose
  • sneezing
  • loss of appetite
  • difficulty sleeping

Your symptoms will usually peak after two to three days and you should begin to feel much better within five to eight days. However  you may have a lingering cough and still feel very tired for a further two to three weeks.

When to visit your GP

If you are otherwise fit and healthy, there is usually no need to visit your GP 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 visit your GP if you have flu-like symptoms and you:

  • are 65 years of age 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 (the body's natural defence against infection and illness)

Flu can be more serious for these groups and antiviral medication may need to be prescribed.

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

Flu or cold?

Many of the symptoms of flu are similar to those of the common cold. Here's how to tell the difference:

Symptoms of a cold

  • appear gradually,
  • affect just your nose and throat  
  • are fairly mild so you can still get around and are usually well enough to go to work

Symptoms of flu

  • come on quickly and include fever and aching muscles.
  • make you feel too unwell to continue your usual activities.
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The flu virus is contained in the millions of tiny droplets that come out of the nose and mouth when someone coughs or sneezes.

These droplets typically spread about one metre (3ft). They hang suspended in the air for a while but then land on surfaces, where the virus can survive for up to 24 hours.

Anyone who breathes in the droplets can catch flu. And anyone who touches the surfaces the droplets have landed on can also catch flu if they pick up the virus on their hands and then touch their nose or mouth.

Everyday items at home and in public places can easily become contaminated with traces of flu virus. These include food, door handles, the remote control, handrails, telephone handsets and computer keyboards.

So, it's very important to wash your hands frequently to prevent catching and spreading flu.

Read more about how to prevent the spread of flu.

New types of flu

If you become infected with a flu virus your body will produce antibodies against it. Antibodies are proteins that recognise and fight off germs that have invaded your blood. 

Your antibodies will remember this flu virus and fight it if it invades your body again.

But, over time the flu virus can change into a different version or strain, which means your body may not recognise it and you can catch flu again.

When the virus changes to a new strain that people have little or no resistance to, it can cause a flu pandemic, which means it can spread globally. This is what happened in the swine flu pandemic of 2009. 

Don't pass it on

Catch it

Germs spread easily. Always carry tissues and use them to catch your cough or sneeze.

Bin it

Germs can live for several hours on tissues. Dispose of your tissue as soon as possible.

Kill it

Hands can transfer germs to every surface you touch. Clean your hands as soon as you can.

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If you are otherwise fit and healthy, you don't need to see your GP when you have flu.

Read more about treating flu

When you should see your GP

You should see your GP if you have flu and any of the following applies to you:

  • Your symptoms have got much worse and include shortness of breath, chest pain or coughing up blood, or you have developed other symptoms that are not typical of flu, such as a rash.
  • Your symptoms have lasted for longer than a week.
  • You have a medical condition that is making your flu worse (see Complications).

Your GP will diagnose flu based on your symptoms and your medical history.

If they suspect that your symptoms are caused by a different condition for example, malaria, if you have recently been travelling, you may need to have further tests or a referral to a hospital specialist.

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If you have flu, the chances are that you'll be able to get well by looking after yourself at home.

In which case you should:

  • rest
  • keep warm
  • drink plenty of water to avoid dehydration
  • try to take paracetamol or anti-inflammatory medicines such as ibuprofen to lower a high temperature and relieve aches

If you are in 'high-risk' group (see below) and are more likely to suffer complications from flu, your doctor may prescribe antiviral medication.

Antibiotics are not prescribed for flu as they have no effect on viruses. However, occasionally it may be necessary to treat complications of flu, especially serious chest infections or pneumonia, with a course of antibiotics.

Antivirals will not cure flu but will help to:

  • reduce the length of time you are ill by around one day
  • relieve some of the symptoms
  • reduce the potential for serious complications.

Antivirals work by stopping the virus from multiplying in your body. There are two main types:

  • Tamiflu
  • Relenza

Tamiflu (oseltamivir)

Tamiflu is taken by mouth (orally) in capsule or liquid form. You need to start taking Tamiflu within 48 hours of getting the first symptoms of flu.

The dose is usually one tablet twice a day for five days. However, if you have kidney disease you may be prescribed a lower dose.

Tamiflu can cause nausea, vomiting, stomach pain and diarrhoea. These side effects should not be serious but see your GP if you are worried.

Relenza (zanamivir)

Relenza is a dry powder that you breath in through an inhaler.  As with Tamiflu, you need to start taking it within 48 hours of your first flu symptoms (36 hours for children). The dose is two inhalations twice a day for five days.

It's a safe treatment that rarely has any side effects.

Antiviral medication can sometimes be taken to prevent flu.

High-risk groups

You may be prescribed antivirals if you are

  • pregnant
  • 65 or over

Or if you have:

  • lung disease
  • heart disease
  • kidney disease
  • liver disease
  • neurological disease (such as motor neurone disease, Parkinson's disease or multiple sclerosis)
  • a weakened immune system
  • diabetes
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Complications of flu mostly affect people in high-risk groups such as the elderly, pregnant women and those who have a long-term medical condition or weakened immune system.

The most common complication is a bacterial chest infection. Occasionally, this can become serious and develop into pneumonia.

A course of antibiotics usually cures a chest infection or pneumonia, but it can very occasionally become life threatening, particularly in the frail and elderly.

Other serious complications are uncommon.

Rare complications

Rare complications include:

  • tonsillitis,
  • otitis media (a build-up of fluid in the ear),
  • septic shock (infection of the blood that causes a severe drop in blood pressure),
  • meningitis (infection in the brain and spinal cord), and
  • encephalitis (inflammation of the brain).
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There are three main ways of preventing flu.

  • Hygiene – handwashing and cleaning
  • Flu vaccination
  • Antiviral medicines

Good hygiene

Preventing the spread of germs is the most effective way to slow the spread of flu. Always:

  • make sure you wash your hands regularly with soap and water,
  • clean surfaces like your keyboard, telephone and door handles regularly to get rid of germs,
  • use tissues to cover your mouth and nose when you cough or sneeze, and
  • put used tissues in a bin as soon as possible.

The flu jab

Annual flu vaccination is available free of charge to the following high-risk people, to protect them from flu:

  • people aged 65 or over
  • pregnant women
  • people with a serious medical condition
  • people living in a residential or nursing home
  • carers of people at risk of complications of the flu
  • healthcare professionals

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

For more information on flu immunisation see Seasonal flu jab.

Vaccination advice for pregnant women

This winter (2012/13), the flu vaccine will be offered to ALL pregnant women at any stage of pregnancy.

Read more about the seasonal flu jab, including background information on the vaccine and how you can get the jab.

Antiviral medication

The National Institute for Health and Clinical Excellence (NICE) recommends the antiviral medicines Relenza or Tamiflu to prevent flu if all of the following apply:

  • There is a lot of flu around.
  • You have a medical condition that puts you at risk of flu such as diabetes, heart disease, lung disease or kidney disease. 
  • You are aged 65 or over. 
  • You have been in contact with someone with a flu-like illness and can start antiviral treatment within 48 hours.
  • You have not been effectively protected by vaccination.

You are not effectively protected by vaccination if you:

  • have not been vaccinated since last winter
  • cannot be vaccinated, or have been vaccinated but it has not taken effect yet
  • have been vaccinated for a different form of flu virus

If there is an outbreak of flu in a residential or nursing home – where the flu virus can often spread very quickly – antiviral medication may be offered to people if they have been in contact with someone with confirmed flu.

For more information, go to the NICE guidelines on antivirals to prevent influenza.

Do I need the flu jab every year?

Yes. If you’re in a high-risk group, you should have the seasonal flu vaccination every year, so that you stay protected.

The viruses that cause flu change every year, so this winter’s flu will be different from last winter's. The 2012/13 flu vaccine will therefore be different as well.

Find out if you should have the annual flu jab.

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