Flu vaccination by injection, commonly known as the "flu jab" is available every year on the NHS to protect adults (and some children) at risk of flu and its complications.

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 on the NHS 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

Flu nasal spray vaccination

The flu vaccine is given as an annual nasal spray to:

• children aged two to 17 years at a particular risk of flu
• healthy children aged two, three and four years old 

How the flu jab helps

Studies have shown that the flu jab does work and will help prevent you getting the flu. It won't stop all flu viruses and the level of protection may vary between people, so it's not a 100% guarantee that you'll be flu-free, but if you do get flu after vaccination it's likely to be milder and shorter-lived than it would otherwise have been.

There is also evidence to suggest that the flu jab can reduce your risk of having a stroke.

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.

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.

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.

Each year, the viruses that are most likely to cause flu are identified in advance and vaccines are made to match them as closely as possible. The vaccines are recommended by the World Health Organisation (WHO).

Is there anyone who shouldn't have the flu jab?

Most adults can have the injected flu vaccine, but you should avoid it if you have had a serious allergic reaction to a flu jab in the past.