Flu outbreaks tend to occur during the winter each year.
The flu (short for influenza) virus spreads rapidly through small, contaminated droplets that infected people cough or sneeze into the air.
Unlike a cold, the symptoms of flu come on very quickly, usually a fever and aching joints and muscles.
Flu can be unpleasant, but if you are otherwise healthy it will usually clear up on its own and you will recover within a week.
However, flu can be more severe in certain people such as:
- anyone over the age of 65
- pregnant women
- people with an underlying health condition (particularly long-term heart or respiratory disease)
- people with weakened immune systems
If you're in one of these risk groups, you're more likely to develop potentially serious complications of flu, such as pneumonia (a lung infection), so it's well worth having a flu jab every year to protect you. Flu jabs for people in risk groups are available free on the NHS.
Find out more about who should have the flu jab.
How the flu vaccine 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 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 vaccine side effects
Serious side effects of the 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 September 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.
The flu jab for 2012/13
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 Organization (WHO).
The 2012/13 vaccine protects against three types of flu virus. This year’s flu jab protects against:
- H1N1 – the strain of flu that caused the swine flu pandemic in 2009
- H3N2 – a strain of flu that can infect birds and mammals and was active in 2011
- B/Wisconsin/1 – a strain of flu that was active in 2010
Who shouldn't have the flu jab
Most people can have the flu vaccine, but you should avoid it if you have had a serious allergic reaction to a flu vaccine in the past.
Read more about who shouldn't have the flu vaccine.
You can find out more by reading the answers to the most common questions that people have about the flu vaccine.
