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    Home > Adult Immunisation > Flu Vaccination

Seasonal Flu Vaccine 2013/2014

Updated February 2014


What is influenza (flu)?

Influenza is a highly infectious acute respiratory illness caused by the influenza virus. Influenza affects people of all ages. Outbreaks of influenza occur almost every year, usually in winter. This is why it is also known as seasonal flu.

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How serious is flu?

Flu is often self limiting with most people recovering in 2-7 days. However, flu can be severe and can cause serious illness and death, especially in the very young and in the elderly. Serious respiratory complications can develop, including pneumonia and bronchitis, to which older people and those with certain chronic medical conditions are particularly susceptible. Pregnant women have also been found to be at increased risk of the complications of flu. Some people may need hospital treatment and a number of mainly older people die from influenza each winter.

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How do people catch flu?

Flu is a highly infectious illness. A person carrying the virus can spread the illness by coughing or sneezing. A person can spread the virus from 1-2 days before they develop symptoms and for up to a week after symptoms develop.

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What are the symptoms of Flu?

Flu symptoms hit you suddenly and severely. Symptoms of flu include

  • sudden fever,
  • chills,
  • headache,
  • myalgia (muscle pain),
  • sore throat
  • non-productive dry cough.

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Is it seasonal flu or the common cold?

It can be difficult at times to tell between the common cold and flu. A cold is a much less severe illness than flu. The flu symptoms come on suddenly with fevers and muscle aches. A cold usually starts gradually with symptoms of a sore throat and a blocked or runny nose.  

Table of Symptoms

The following table provides information on how to distinguish between seasonal flu and cold symptoms


Seasonal flu



High fever lasts 3-4 days





General Aches, Pains

Usual; often severe


Fatigue, Weakness

Can last up to 2-3 weeks

Quite mild

Extreme Exhaustion

Early and prominent


Stuffy Nose






Sore Throat



Chest Discomfort, Cough

Common; can become severe

Mild to moderate; hacking cough

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Who is most at risk from flu?

Anyone can get the flu but it is more severe in people aged 65 years and over and anyone with a chronic medical condition. Chronic medical conditions include chronic heart conditions, chronic respiratory disease, diabetes mellitus and immunosupression due to disease or treatment. Pregnant women have also been found to be at increased risk of the complications of flu. These groups of people are targeted for influenza vaccination.

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How can flu be prevented?

Flu can be prevented by vaccination. Flu vaccine is a safe, effective way to help prevent flu infection, avoiding hospitalisation, reducing flu related deaths and illnesses.

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What is the seasonal (annual) flu vaccine?

Each year the seasonal (annual) flu vaccine contains three common influenza virus strains. The flu virus changes each year this is why a new flu vaccine has to be given each year.

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What strains are in the 2013/14 year’s seasonal flu vaccine?

This year’s seasonal flu vaccine contains 3 strains of flu viruses as recommended by the World Health Organization (WHO) as the strains most likely to be circulating this season. The three strains are

  • An A/California/7/2009 (H1N1)pdm09-like virus;

  • An A(H3N2) virus antigenically like the cell-propagated prototype virusA/Victoria/361/2011;

  • A B/Massachusetts/2/2012-like virus.

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Who should be vaccinated?

Vaccination is strongly recommended for:

  • persons 65 and over,
  • those aged 6 months to 65 years 
    • with a long term medical condition such as diabetes. heart, kidney, lung or neurological disease  
    • whose immune system is impaired due to disease or treatment 
    • with a Body Mass Index (BMI) over 40
  • residents of nursing homes and other long stay institutions
  • pregnant women.(can be given at any stage of pregnancy),
  • healthcare workers
  • carers
  • people with regular close contact with poultry, water fowl or pigs.

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How does seasonal flu vaccine work?

Seasonal flu vaccine helps the person’s immune system to produce antibodies to the flu virus. When someone who has been vaccinated comes into contact with the virus these antibodies attack the virus.

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How effective is seasonal flu vaccine?

Seasonal flu vaccine prevents flu illness in approximately 70% - 90% of people.

The effectiveness varies depending on the age and health of the person being vaccinated and the strains of flu virus that are circulating. Older persons and those with certain long term diseases have lower immune responses so the vaccine may not be as effective but it will still prevent severe illness and hospitalisation.

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How long is the flu season?

In the Northern hemisphere the flu season lasts from October to the end of April. Flu vaccine is recommended for all those in the at risk groups until the end of April Women who become pregnant at any stage during the flu season should get flu vaccine.

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How safe is flu vaccine?

Seasonal flu vaccines have been given for more than 60 years to millions of people across the world. Reactions are generally mild and serious side effects are very rare.  

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Is there thiomersal in the seasonal flu vaccine?

No. There is no thiomersal in the vaccine used in the 2013/2014 flu campaign.

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Will the flu vaccine give me the flu?

No, flu vaccine will not give you the flu. Flu vaccine contains killed or inactivated viruses and therefore cannot cause flu. It does, however, take 10 – 14 days for the vaccine to start protecting against flu.  

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When should I get vaccinated?

The vaccine should be given in late September/October each year.

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What should I expect after vaccination?

The most common side effects will be mild and will include soreness, redness or swelling where the injection was given. Headache, fever, aches and tiredness may occur. Some people may experience mild sweating and shivering as their immune system responds to the vaccine but this is not flu and will pass in a day or so.

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How long does it take the vaccine to work?

The vaccine starts to work within two weeks. 

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Who should NOT get seasonal flu vaccine?

The vaccine should not be given to those with a history of severe allergic (anaphylaxis) reaction to a previous dose of the vaccine or any of its constituents.

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What about people with egg allergy?

People with egg allergy can get seasonal flu vaccine. This may be given by your GP or you may need referral to a hospital specialist.

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When should vaccination be postponed?

There are very few reasons why vaccination should be postponed. Vaccination should be re-scheduled if you have an acute illness with a temperature greater than 38°C. 

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How do I get vaccinated?

  • People aged 18 years or older may attend either their GP or Pharmacist.
  • People under 18 years of age should attend their GP for vaccination.

Please make an appointment now.

  • The vaccine is free for all those in the recommended groups.
  • The vaccine and consultation are free to those within the recommended groups who have a ‘Medical Card’ or ‘Doctor Only Card’.
  • Family doctors and Pharmacists charge a consultation fee for seasonal flu vaccine to those who do not have a ‘Medical Card’ or ‘Doctor Only Card’. 

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If you are 65 or older or have a long term medical condition you should also ask your doctor about the pneumococcal vaccine which protects against pneumonia, if you have not previously received it.

Keep well this winter

  1. Eat well: eat at least one hot meal a day.
  2. Keep warm: wear several layers when outside and keep at least one room heated during the day.
  3. Keep active.
  4. Get vaccinated. 

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Where can I find out more? 

You can download our information materials for this years campaign. The following publications are available for download

More information is available from the following links

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This section was updated on 20th February 2014
Health Protection Surveillance Centre The Department of Health and Children Irish College Of General Practitioner