Influenza Immunisation

What is influenza?

Influenza (flu) is an illness caused by the influenza virus. There are different strains of influenza virus. They are transmitted by coughing and sneezing. Symptoms of influenza include a high temperature (fever), muscle aches, cough, headache and extreme tiredness. Most people recover fully, but complications such as a chest infection or pneumonia develop in some cases. Complications are sometimes serious and even fatal in some cases. Complications are more likely to develop in the elderly and also in people with some underlying medical problems such as chest or heart conditions. Many people in the UK die each year (mostly elderly people) from the complications of influenza.

Each winter a different strain of the influenza virus causes an outbreak of influenza which affects many people. This is called seasonal flu.

Swine flu is caused by a particular type of influenza virus and is different to the seasonal influenza virus. At the time of writing (November 2009), the swine flu virus is the dominant virus causing flu in the UK.

Note: bird flu (avian influenza) is different and is more serious. See separate leaflet called 'Bird Flu (Avian Influenza)' for details.

Immunisation against seasonal flu

Flu immunisation (the 'flu jab') gives excellent protection against seasonal flu and lasts for one year. The vaccine is normally ready and given in October and November each year. It is made from the strain of influenza virus that is expected in the coming winter. Each year this is slightly different so a new vaccine needs to be made every year. You need a yearly immunisation to keep protected.

Flu immunisation does not prevent other virus infections which can cause coughs, colds and flu-like illnesses. It protects only against the influenza virus that is expected in the coming winter. The vaccine does not actually contain any living influenza virus. This means that it cannot cause flu or any other infections. It is a coincidence if you develop a cough or cold shortly after having a flu immunisation. It usually takes up to two weeks for your body to develop full protection against the influenza virus after the vaccine is given.

Who should be immunised against the seasonal flu virus?

The aim is to protect people who are more likely to develop complications from flu. Current advice in the UK is that you should be immunised against the seasonal flu virus each autumn if you:

• Are aged 65 or over.
• Have any chronic (ongoing) lung diseases.
  Examples include chronic bronchitis, emphysema, cystic fibrosis and severe asthma (needing regular steroid inhalers or tablets). It is also recommended for any child who has previously been admitted to hospital with a chest infection.
• Have a chronic heart disease.
  Examples include angina, heart failure or if you have ever had a heart attack.
• Have a serious kidney disease.
  Examples include nephrotic syndrome, kidney failure, a kidney transplant.
• Have a serious liver disease such as cirrhosis.
• Have diabetes and are taking either insulin or tablets for it.
• Have a poor immune system.
  Examples include if you who are receiving chemotherapy or steroid treatment (for more than a month), if you have HIV/AIDS or if you have had your spleen removed.
• Have certain serious diseases of the nervous system such as multiple sclerosis.
• Live in a nursing home or other long stay residential care accommodation.

In addition to the main 'at risk' groups of people listed above:

• You should be immunised if you are the main carer for an elderly or disabled person whose welfare may be at risk if you fall ill with influenza.
• Staff involved in direct patient care may be offered a flu jab from their employer.
• If you work in close contact with poultry you should be immunised. This is a precautionary public health measure by the Department of Health.

Are there any side-effects from seasonal flu immunisation?

Immunisation against the seasonal influenza virus usually causes no problems. You may have a temporary mild soreness at the injection site. Sometimes, it can cause a mild fever and slight muscle aches for a day or so. This soon settles and does not lead to flu or other problems. Serious reactions have been reported but are rare. For example, a severe allergic response, inflammation of nerves and inflammation of the brain are very rare reactions.

Who should not have the seasonal flu immunisation?

The following groups of people should also not be immunised:

• If you are have a severe allergy to eggs (as the vaccine is made in hens' eggs).
• If you have had a previous allergic reaction to an influenza virus vaccine.
• If you have had a previous severe allergic reaction to neomycin, kanamycin, gentamicin, polymyxin B or thiomersal, as some influenza virus vaccines may contain these in trace amounts.

The influenza vaccine can be given at the same time as other vaccines; it is often given at the same time as the pneumonia vaccine. It is also safe to give if you are either pregnant or breast-feeding.

Immunisation against swine flu

Vaccines have been developed to protect against swine flu. Immunisation against swine flu with the new vaccines began in the UK in the autumn of 2009. People at greatest risk of developing complications are being given priority. That is, the same main 'at risk' groups as listed above for seasonal flu. In addition, pregnant women and children aged under five years old. These people are being invited to GP surgeries to be immunised. Also, healthcare workers who come into contact with people with swine flu are being offered immunisation. People who are not in the priority groups may be offered immunisation at a later time.

Details of the immunisation (in various languages) is on the Department of Health's website:
Web: www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_107404

So, over the autumn and winter 2009/2010 many people are being advised to have two immunisations - one against seasonal flu and one against swine flu.

Further sources of information

NHS immunisation website

Web: www.immunisation.nhs.uk

References

• Immunisation against infectious disease - 'The Green Book', Department of Health (various dates)
• Influenza, Clinical Knowledge Summaries (August 2009)
• Immunizations - seasonal influenza, Clinical Knowledge Summaries (July 2009)
• Swine flu - Clinical information and guidance for professionals, Various guidelines from the Department of Health (Various Dates)
• The influenza immunisation programme 2009/10, Department of Health (April 2009); PL CMO (2009)1, PL CNO (2009)1, PL CPHO (2009)1