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Pandemic flu

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What is swine flu?

Note: If you have a new or ongoing cough, a high temperature (fever) or you've noticed a change in your sense of smell or taste, you may have coronavirus (COVID-19). Read more about coronavirus or use our Coronavirus Risk Assessment to check your risk.

Swine flu is a relatively new strain of influenza (flu) that was responsible for a flu pandemic during 2009-2010.

It is sometimes known as H1N1 influenza because it is the H1N1 strain of virus.

On 10 August 2010, the World Health Organization (WHO) declared that the swine flu pandemic was officially over. However, this does not mean that swine flu can be ignored.


It is recommended that people in high-risk groups be vaccinated against swine flu. This includes all pregnant women, at any stage of pregnancy.

Pregnant women in high-risk groups and those not in high-risk groups are advised to take the seasonal flu jab, which protects against swine flu.

This is because there is good evidence that all pregnant women are at increased risk from complications if they catch swine flu. For more information, see swine flu advice for pregnant women.

Until now, only pregnant women in high-risk groups were advised to take the seasonal flu vaccine. For general information about flu, see seasonal flu and seasonal flu jab.

What to do if you have swine flu

People with swine flu typically have a fever or high temperature (over 38C or 100.4F) and may also have aching muscles, sore throat or a dry cough (see symptoms of swine flu). The symptoms are very similar to other types of seasonal flu. Most people recover within a week, even without special treatment.

Contact your doctor if you think you have swine flu and you are worried. They will decide the most appropriate action to take.

High-risk groups

Some people are more at risk of complications if they catch flu. People are particularly vulnerable if they have:

Also at risk are:

  • patients who have had drug treatment for asthma in the past three years
  • pregnant women
  • people who are 65 years of age or over

See preventing swine flu for a full list of people advised to have this year's flu jab.

Preventing the spread of swine flu

The most important way to stop flu spreading is to have good respiratory and hand hygiene. This means sneezing into a tissue and quickly putting it in a bin. Wash your hands and work surfaces regularly and thoroughly to kill the virus.

Anyone who is concerned about flu symptoms should contact their doctor, who will determine the most appropriate action to take.

For more information about how the H1N1 virus spreads, see causes of swine flu.

Swine flu symptoms

The symptoms of swine flu are similar to those of other types of seasonal flu.

The effects of the illness are often mild, but some people (see below) are more at risk of serious illness.

If you or a member of your family has a fever or high temperature (over 38C/100.4F) and two or more of the following symptoms, you may have swine flu:

  • unusual tiredness
  • headache
  • runny nose
  • sore throat
  • shortness of breath or cough
  • loss of appetite
  • aching muscles
  • diarrhoea or vomiting

It makes sense to have a working thermometer at home, as an increase in temperature is one of the main symptoms. If you are unsure how to use a thermometer, read about [how to take someone's temperature].

What to do

If you have flu-like symptoms, stay at home, get plenty of rest and use over-the-counter painkillers to relieve symptoms. If you are concerned, contact your doctor. They will determine the most appropriate action to take.

High-risk groups

For most people, swine flu is a mild illness. Some people get better by staying in bed, drinking plenty of water and taking over-the-counter flu medication.

However, some groups of people are more at risk of serious illness if they catch flu.

It is already known that you are particularly at risk if you have:

Also at risk are:

  • patients who have had drug treatment for asthma within the past three years
  • pregnant women
  • people who are 65 years of age or over


For most people, the illness appears to be mild. For a minority of people, the virus can cause severe illness. In many of these cases, other factors contribute to the severity of the illness.

When complications occur, they are usually caused by the virus affecting the lungs. Infections such as pneumonia can develop.

Swine flu causes

The swine flu virus is spread in exactly the same way as the common cold and other flu viruses.

The 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 1 metre (3 feet). 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 touches these surfaces can spread the virus by touching anything else.

Everyday items at home and in public places may have traces of the virus. These include food, door handles, remote controls, hand rails and computer keyboards.

People usually become infected by picking up the virus on their hands from contaminated objects and then placing their hands near their mouth or nose. It is also possible to breathe in the virus if it is suspended in airborne droplets.

Good hygiene

Preventing the spread of germs is the most effective way to slow the spread of diseases such as swine flu:

  • Ensure everyone washes their hands regularly with soap and water.
  • Clean surfaces regularly 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.

Read more about preventing swine flu.

Treatment for swine flu

Swine flu is treated in a similar way to ordinary flu. Antiviral and antibiotic medications are also available if further treatment is needed or complications develop.

As with ordinary flu, people who have swine flu should get lots of rest and use standard paracetamol-based cold remedies to reduce their temperature and help relieve symptoms.

Some over-the-counter treatments used by adults can be given to children for the relief of the symptoms. Follow the instructions that come with each medicine.

However, children under 16 must not be given aspirin or ready-made flu remedies containing aspirin. Always read the label or check with the pharmacist that a medicine is suitable for children.


Antivirals are not a cure for swine flu, but will help:

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

Tamiflu and Relenza are both medicines of the same type, but Relenza comes as an inhaler (rather than a pill) and is recommended for use in pregnancy.


Antibiotics are used to treat swine flu patients who develop complications. They help combat bacterial infections such as pneumonia.

In hospitals, antibiotics will be used to treat the most ill patients and may reduce the length of hospitalisation.

Advice for pregnant women

Pregnant women are at greater risk from swine flu because their immune system is suppressed during pregnancy.

This means that pregnant women are more likely to catch flu and, if they do, they are at greater risk of developing complications (see below).

However, during pregnancy, the immune system still functions and the risk of complications is very small. Most pregnant women will only have mild symptoms.

Symptoms and risks

If you are pregnant and you catch swine flu, the symptoms are likely to be similar to those of normal flu. You will usually have a fever (a high temperature of or above 38C/100.4F), plus two or more of the following symptoms:

  • unusual tiredness
  • headache
  • runny nose
  • sore throat
  • shortness of breath or cough
  • loss of appetite
  • aching muscles
  • diarrhoea or vomiting

Most pregnant women will have only mild symptoms and recover within a week. However, there is evidence from previous flu pandemics that pregnant women are more likely to develop complications.

Possible complications include:

In pregnant women, these are more likely to happen in the second and third trimester.

If a pregnant woman develops a complication of swine flu, such as pneumonia, there is a small chance this will lead to premature labour or miscarriage. There is not yet enough information to know precisely how likely these birth risks are.

It is therefore important to be well prepared and to take precautions against swine flu.

Vaccination and pregnancy

Pregnant women are advised to take the seasonal flu jab, whatever the stage of pregnancy. This includes pregnant women not in high-risk groups.

This year's seasonal flu jab offers protection against the swine flu virus, as well as other strains of flu virus.

There is no evidence that inactivated vaccines, such as the seasonal flu vaccine, will cause any harm to pregnant women or their unborn baby. Every year, the seasonal flu vaccine is given to pregnant women who are at risk of flu.

The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency has given a clear recommendation that the GlaxoSmithKline vaccine Pandemrix can be given safely to all pregnant women.

Special precautions

If you are pregnant, you can reduce your risk of infection by avoiding unnecessary travel and avoiding crowds where possible.

Pregnant women should also follow general measures to prevent swine flu, as described below. Good hygiene is essential.

You can reduce, but not eliminate, the risk of catching or spreading swine flu by:

  • always covering your nose and mouth with a tissue when coughing or sneezing
  • throwing away dirty tissues promptly and carefully
  • maintaining good basic hygiene, for example
  • washing hands frequently with soap and warm water to reduce the spread of the virus from your hands to your face, or to other people
  • cleaning hard surfaces, such as door handles, frequently using a normal cleaning product

If you think you may have swine flu, call your doctor for an assessment. Your doctor will advise you what to do if they think you have flu.

Unless you have swine flu symptoms, carry on attending your antenatal appointments to monitor the progress of your pregnancy.


If you are pregnant and diagnosed with swine flu, you may be given a course of antiviral medication.

If you have an uncomplicated illness due to influenza and do not have an underlying disease, you can take either Relenza or Tamiflu. Relenza is recommended as a first choice.

Relenza is inhaled using a disk-shaped inhaler. It is recommended for pregnant women because it easily reaches the throat and lungs, where it is needed, and does not reach significant levels in the blood or placenta. Relenza should not affect your pregnancy or your growing baby.

However, Tamiflu should be offered instead of Relenza if you:

  • have a condition such as asthma or chronic obstructive pulmonary disease
  • have difficulty taking an inhaled antiviral
  • develop a severe or complicated disease due to influenza (where you will probably be treated in hospital)

An expert group reviewed the risk of antiviral treatment in pregnancy. It is much smaller than the risk posed by the symptoms of swine flu.

Some people have had wheezing or serious breathing problems when they have used Relenza. Relenza is therefore not recommended for people with asthma or chronic obstructive pulmonary disease (COPD). Other possible side effects of Relenza include headaches, diarrhoea, nausea and vomiting.

In a small number of cases, nausea is a side effect of Tamiflu.

If you take an antiviral and have side effects, see your healthcare professional to check that you are OK.


You can also take paracetamol to reduce fever and other symptoms. This is safe to take in pregnancy.

However, pregnant women should not take non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Nurofen).


The most effective way to prevent the spread of infections, such as flu, is to practise good hygiene. A seasonal flu jab is also available for people who are most at risk.

You can protect yourself and your family by:

  • ensuring everyone washes their hands regularly with soap and water
  • cleaning surfaces regularly

You can prevent a virus spreading to others by:

  • always carrying tissues
  • using tissues to cover your mouth and nose when you cough and sneeze
  • binning the tissues as soon as possible
  • washing your hands regularly

The phrase 'catch it, bin it, kill it' is a simple way to remember this.

Seasonal flu jab

This winter, the swine flu virus has been included in this year's seasonal flu jab. It means that the vaccine will protect you from swine flu, as well as other strains.

Vaccination is given free of charge to the following at-risk people, to protect them from flu:

  • people with a serious medical condition (see paragraph below)
  • people aged 65 or over
  • pregnant women (see below)
  • people living in a residential or nursing home
  • the main carers for an elderly or disabled person whose welfare may be at risk if the carer becomes ill
  • healthcare or social care professionals directly involved in patient care
  • those who work in close contact with poultry, such as chickens

This winter, the seasonal flu vaccine will be extended to pregnant women not in the high-risk groups.

Usually, only pregnant women in high-risk groups are offered the seasonal flu vaccine.

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

Conditions that increase your risk

The seasonal flu jab is offered free of charge to anyone over the age of six months with the following medical conditions, as they are at higher risk of catching flu:

Antiviral medication

People who are not effectively protected by vaccination include:

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

If there is an outbreak of seasonal flu in a residential or nursing home, oseltamivir and zanamivir may be offered to people if they have been in contact with someone with confirmed flu. This is because these homes are closed places in which flu can spread quickly.

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