The Flu Jab - What is it?

How serious is the flu?

The Flu is very often self limiting with most people recovering in 2-7 days. However, it 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.

What is the Flu Jab?

The flu jab, or influenza vaccine, is a mixture of dead flu viruses that prepares the immune system to fight the actual virus if it enters the body. It's like giving a search-and-rescue dog a shoe to sniff so that the dog remembers the scent and can find the owner of the shoe. The immune system remembers the viruses in the flu shot, and is ready to attack if one shows up in your body. The viruses are destroyed quickly, before you come down with any symptoms. Getting the shot does not guarantee that you won't get the flu, but it does mean that you have a much smaller chance of getting sick from it.

How it works

About a week to 10 days after you have had the flu injection, your body starts making antibodies to the virus in the vaccine. Antibodies are proteins that recognise and fight off germs that have invaded your blood, such as viruses. They help protect you against any similar viruses you then come into contact with. The flu virus changes every year, so you need to have a flu jab annually to make sure that you are protected against the latest strain of the virus.

How is it made?

The seasonal flu vaccine contains different types of flu virus, which are grown in hens' eggs. They are then inactivated (killed) and purified before being made into the vaccine.

There are currently three types of vaccine that are as effective as each other but made in different ways:

• The first type is made by inactivating whole viruses with organic solvents or detergents ('disrupted live' vaccines).
• The second type is made by extracting and purifying components of the flu viruses ('surface antigen' vaccines).
• The third type uses virosomes, which are the empty envelopes of flu viruses that lack the genetic material of the original virus.

Because the flu virus is continually changing and different types circulate each winter, a new flu vaccine has to be produced each year.

Who needs the Flu Jab most?

• The young - they have not developed any natural immunity to flu yet
• The elderly - they have higher risks of developing severe complications such as pneumonia, have a worse immune response, and often have underlying diseases which weaken them
• High risk groups - other people whose medical condition makes them more vulnerable to flu. Conditions include:

• Chronic respiratory disease including asthma
• Chronic heart disease
• Chronic kidney disease
• Diabetes
• Lowered immunity due to prolonged steroid treatment or cancer treatment

Who should not have the seasonal flu jab?

• You should not have the seasonal flu vaccine if:
• You have had a previous allergic reaction to a flu vaccine (rare)
• You have a serious allergy to hens' eggs (very rare), because the vaccine is prepared in hens' eggs.
• Generally, if you are healthy, under 65 and do not fall into any of the at-risk groups, it is not necessary for you to have a flu jab as your body can fight off the virus if you become ill with it.
• If you are ill with a fever, do not have your flu jab until you have recovered.
• If you are pregnant, talk to your GP about having the vaccination. No problems have been reported in pregnant women who have had the flu jab.

Side Effects of the Flu Jab

• Some minor side effects that could occur are:
• Soreness, redness, or swelling where the shot was given
• Fever
• Aches

If these problems occur, they begin soon after the shot and usually last 1 to 2 days. Almost all people who receive the flu jab have no serious problems from it. However, on rare occasions, flu vaccination can cause serious problems, such as severe allergic reactions.

How long will it protect me for?

The flu jab will protect you for about a year.

If I had it last year do I need it again?

Yes. The viruses that cause flu change every year, which means the flu (and the vaccine) this winter will be different from last winter's.