Influenza, commonly known as the flu, is caused by a highly contagious virus that is spread by contact with fluids from coughs and sneezes. Every year, the flu causes widespread illness in the community. Annual immunisation is strongly recommended for older people and other people who are at risk of serious complications from the flu (such as pneumonia).
An influenza epidemic occurs when an outbreak of the illness is widespread in a certain community. A pandemic occurs when the illness is more geographically widespread and on more than one continent. Influenza epidemics occur, on average, every three years whereas pandemics have occurred only four times in the past 100 years.
Annual immunisation against the flu is strongly recommended for people in at-risk groups such as older people, pregnant women and those who work or live with people in at-risk groups. Annual influenza vaccination is recommended for any person from six months of age who wishes to reduce the likelihood of becoming ill with the flu.
Immunisation against the flu
Immunisation of people who are at risk of complications from the flu is the most important way we have to reduce the number of flu infections and deaths.
Influenza viruses change every year because the influenza virus has a unique ability to change its surface structure. This means that even if you had the flu or an immunisation one year, your body’s immune system might be unable to fight the changed version of the virus that will be circulating the following year.
Each year, a new vaccine is developed (usually called the seasonal vaccine) and is available for those who wish to be immunised. The seasonal influenza vaccine includes protection against four strains of influenza.
Recent evidence suggests protection against influenza may start to decrease from three to four months following vaccination. Annual vaccination before the onset of each influenza season is recommended. While influenza continues to circulate, it is never too late to vaccinate.
The influenza vaccine cannot give you a dose of flu because it does not contain live virus. Some people may still contract the flu because the vaccine may not always protect against all strains of the influenza virus circulating in the community.
An annual flu vaccination is provided through the National Immunisation Program for most people in the community who are considered to be at an increased risk of complications. In Victoria, an annual vaccination against the flu is free for:
all Victorian children aged six months to less than five years of age
people who have medical conditions that put them at risk of serious complications of the flu
Aboriginal and Torres Strait Islander people aged six months to under five years and 15 years and over
pregnant women – at any stage of pregnancy
people 65 years and over.
Contact your doctor or immunisation provider for further information about eligibility. People not covered by these categories can also have an annual flu immunisation but it is not available for free.
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