Introduction
Flu (also known as influenza) is a highly infectious illness caused by the flu virus. It spreads rapidly through small droplets coughed or sneezed into the air by an infected person.
Studies have shown that flu vaccines provide effective protection against the flu, although protection may not be complete and may vary between people. Protection from the vaccine gradually decreases and flu strains change over time. Therefore, new vaccines are made each year and people at risk of flu are encouraged to be vaccinated every year.
The flu vaccination is offered to people in at-risk groups. These people are at greater risk of developing serious complications if they catch flu, such as pregnant women and elderly people.
Find out who should have the flu jab.
This year's flu jab (2011)
This winter s flu jab protects against the same three strains of flu as last year s vaccines. These include the H1N1 strain of the flu virus. H1N1 is the same strain of flu that caused the 2009 swine flu pandemic.
H1N1 is included because it is likely to be one of the major flu strains circulating in Britain this winter.
The best time to have a flu jab is in the autumn, from September to early November.
Find out more about getting the flu jab.
Is this year's vaccine safe?
Although no medical procedure is totally free of risk, flu vaccines are generally very safe. The most common reaction to the jab is a sore arm, or you may feel hot for a day or two after the vaccination.
This year s flu jabs have been tested and approved for use across the UK and in Europe. The jab cannot give you flu because it doesn't contain any active viruses.
The Department of Health recommends that everyone who is eligible for a flu jab should have it as soon as the vaccine is available.
If you are in an at-risk group and do not have the jab, you will have a greater risk of developing serious complications or even dying if you get flu this winter.
If you haven't had the flu vaccine and you are in a risk group, make an appointment to get vaccinated.
Find out more about the flu vaccine, including how the vaccine is made and how it protects you.
Help fight flu
Sign up for the flu survey to help researchers at the London School of Hygiene and Tropical Medicine track the spread of flu and discover more about it. The survey takes just a few minutes each week and anyone can take part.
