The flu (or common flu) is a viral infection that is spread from person to person in secretions of the nose and lungs, for example when sneezing. Medically, the common flu is referred to as influenza. Flu is a respiratory infection, that is, an infection that develops primarily in the lungs.
Flu can be unpleasant, but if you are otherwise healthy it will usually clear up on its own within a week.
However, flu can be more severe in certain people such as:
- anyone over the age of 65
- pregnant women
- children and adults with an underlying health condition (particularly long-term heart or respiratory disease)
- children and adults with weakened immune systems
Anyone in these risk groups is more likely to develop potentially serious complications of flu, such as pneumonia (a lung infection), so it's recommended that they have a flu vaccine every year to protect them.
The flu vaccine is given free as an annual injection to:
- adults over the age of 18 at risk of flu (including everyone over 65)
- children aged six months to two years at risk of flu
Find out more about who should have the flu jab.
Flu nasal spray vaccination
The flu vaccine is given as an annual nasal spray to:
children aged two to 18 years at risk of flu
healthy children aged two and three years
Read more about the flu nasal spray for children.
How the flu jab works
Studies have shown that the flu jab definitely works and will help prevent you getting the flu. However, it won't stop all flu virus's and the level of protection may vary between people, so it's not a 100% guarantee that you'll be flu-free.
Over time, protection from the injected flu vaccine gradually decreases and flu strains often change. So, new flu vaccines are produced each year which is why people advised to have the flu jab need it every year too.
Read more about how the flu jab works.
Flu jab side effects
Serious side effects of the injected flu vaccine are very rare. You may have a slight temperature and aching muscles for a couple of days after having the jab, and your arm may be a bit sore where you were injected.
Read more about the side effects of the flu jab.
When to have a flu jab
The best time to have a flu vaccine is in the autumn, from the beginning of October to early November, but don't worry if you've missed it, you can have the vaccine later in winter if there are stocks left.