Influenza Immunisation

What is influenza?

Influenza (flu) causes a high temperature (fever), muscle aches, cough, and various other symptoms. Each year a different strain of the influenza virus causes a winter outbreak of flu. If you are normally well, flu usually lasts a few days, and then goes as your immune system clears the virus. However, some people who have flu develop serious complications such as pneumonia. 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. Influenza immunisation only protects against 'human flu' strains of the influenza virus.

The immunisation

Flu immunisation (the 'flu jab') gives good protection against flu, and lasts for one year. The vaccine is normally ready by the autumn each year. It is made from the strain of influenza virus that is expected in the coming winter. You need a yearly immunisation to keep protected.

Flu immunisation does not prevent other virus infections which can cause coughs and colds. It protects only against the influenza virus that is expected in the coming winter. The flu immunisation does not cause illness. It is a coincidence if you develop a cough or cold shortly after having a flu immunisation.

Who should be immunised against the influenza virus?

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

• Are aged 65 or over.
• Have a chronic (ongoing) lung disease. For example: chronic obstructive pulmonary disease (COPD), emphysema, chronic bronchitis, asthma which requires regular use of inhaled steroids or steroid tablets (or if you have previously been admitted to hospital because of asthma), cystic fibrosis, interstitial lung fibrosis, pneumoconiosis, etc.
• Have a chronic heart disease. For example: if you require regular medication or follow-up for ischemic heart disease (angina, heart attacks, etc), congenital heart disease, chronic heart failure, or heart disease caused by high blood pressure.
• Have a serious kidney disease. For example: nephrotic syndrome, kidney failure, if you have had a kidney transplant.
• Have a serious liver disease such as cirrhosis.
• Have diabetes which requires insulin or tablets to control it.
• Have a poor immune system. For example: if you have no spleen, are taking chemotherapy or steroid treatment, if you have HIV/AIDS, etc.
• 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. For example, if you were to develop flu.
• Healthy 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 advised 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 rare reactions to the vaccine.

Who should not have the influenza immunisation?

If you are normally healthy and under 65 then you do not need to be immunised against the influenza virus. This is because you are unlikely to develop complications should you get flu. That is, apart from certain carers, health care workers and poultry workers as mentioned above.

The following groups of people should also not be immunised:

• If you are hyper-sensitive to egg (rare). This is because the vaccine is made in hens' eggs.
• If you have had a previous allergic reaction to an influenza virus vaccine (rare).
• 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.

Further sources of information

Government immunisation website

Web: www.immunisation.nhs.uk