Influenza Immunisation

What is influenza?

Influenza (flu) is caused by the influenza virus. It is transmitted by coughing and sneezing. Influenza causes a high temperature (fever), muscle aches, cough, headache and extreme tiredness. Each year a different strain of the influenza virus causes a winter outbreak of flu. If you are normally healthy, flu usually only lasts for a few days and then improves as your immune system clears the virus from the body. However, influenza can be much worse in the elderly and also in people with chest or heart conditions. Other infections can develop more frequently after having flu. These include pneumonia and bronchitis. Many people in the UK die each year (mostly elderly people) from the complications of flu.

Note: bird flu (avian influenza) is different to the usual 'human' flu. See separate leaflet on 'Bird Flu (Avian Influenza)' for more detail. Influenza immunisation only protects against 'human' flu strains of the influenza virus.

The immunisation

Flu immunisation (the 'flu jab') gives excellent protection against 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 can not cause influenza. 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 influenza after the vaccine is given. The influenza vaccine is very effective at reducing the death rate from influenza and also complications of influenza.

Who should be immunised against the influenza virus?

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

• Are aged 65 or over.
• Have a 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 have the flu jab if you are the main carer of 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 influenza immunisation?

Immunisation against the 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 influenza 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.

Further sources of information

NHS immunisation website

Web: www.immunisation.nhs.uk