Seasonal flu is a highly infectious respiratory illness caused by a flu virus. It spreads rapidly through the coughs and sneezes of infected people.
Seasonal flu immunisation, or the flu jab, is the injection of a vaccine against flu. It gives good protection from flu that lasts for one year.
The flu jab is offered to people in at risk groups, who are at greater risk of developing serious complications from flu. To stay protected, they need to have it every year.
The vaccine, which is normally available in the autumn, is made from the strains of flu that are expected in winter.
How the vaccine protects you
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 effective is it?
The flu vaccines currently available give 70-80% protection against infection, with flu virus strains closely matching those in the vaccine.
In the elderly, protection against infection may be less, but immunisation reduces the chances of pneumonia, hospital admissions and death from seasonal flu.
For most people, seasonal flu is unpleasant but not serious and they recover within a week.
However, certain people are at greater risk of developing serious complications of flu, such as bronchitis and pneumonia. These may require hospital treatment. A large number of elderly people die from flu every winter.
The seasonal flu vaccine is offered free of charge to these at-risk groups to protect them from catching flu and developing these complications.
At Risk Groups
It is recommended you have a flu jab if you:
- are 65 or over
- have a serious medical condition such as chronic chest problems, chronic heart, liver or kidney disease
- are immuno-suppressed
- are diabetic
- are pregnant
- live in a residential or nursing home
- are the main carer for an elderly or disabled person whose welfare may be at risk if you fall ill
- are a healthcare or social care professional directly involved in patient care, or
- work with poultry (see below)
If you are the parent of a child (over six months) with a long-term condition, speak to your GP about the flu jab. Your child's condition may get worse if they catch flu.
If you are the carer of an elderly or disabled person, make sure they have had their flu jab.
You are entitled to a free flu vaccination if you work in close contact with poultry. This includes people who:
- work in areas where poultry are kept for rearing or egg production,
- handle or catch live poultry,
- sort eggs in poultry houses, or
- slaughter or clean poultry.
Free flu vaccination is offered to poultry workers because they are at slightly greater risk of catching bird flu if there is an outbreak.
If the bird flu and human flu viruses were to mix, a new flu virus could be made. A flu vaccination protects against human flu, reducing the risk of the viruses mixing even if a person had both human flu and bird flu at the same time.