What is the flu vaccine?
The influenza vaccine (also called the flu vaccine) is used to prevent infection caused by the influenza (flu) virus. The flu can cause serious illness, especially in young children, older adults and people with chronic health problems, but anyone can become seriously ill from the flu virus. Even if you are not feeling sick, you could still be infected with the flu virus and pass it on to others. Read more about the flu.
Vaccination is the best way to prevent infection and reduce the seriousness of illness if you become infected. It will greatly improve your chances of not getting the flu, but it does not give 100% protection.
Being vaccinated causes your body to produce antibodies against the flu virus. This means your body can respond faster and more effectively to the flu. By first coming across a non-infectious version of the virus in the vaccine, it learns to recognise it. When it comes across it again, your body can react much faster and in a more effective way.
Even if you get the flu after being vaccinated, you usually get a mild form of it and recover faster, and are less likely to have serious complications.
Why do I need to get vaccinated every year?
You need to get the flu vaccine every year because protection from the previous vaccination becomes less effective over time. Each year the influenza viruses can change. The strains in the vaccine usually change each year in response to the changing virus pattern. Read more about vaccination against influenza.
When is the flu vaccine given?
It is possible to come into contact with flu viruses all year round, but the chance of the flu virus circulating in the community is highest during winter. For most people, the best time to be vaccinated against the flu is just before the start of the winter season. In New Zealand, this is between April and June. It takes 2 weeks after vaccination for the vaccine to be fully effective. You may still get the flu in this time if you come into contact with the virus, so get it done early in time for winter.
If you become pregnant after winter and have not received the current flu vaccine, it is recommended that you have it by 31 December.
Who should get the flu vaccine?
Anyone over the age of 6 months can have the flu vaccine. The flu vaccine is free for these people, who are considered to be at greater risk of complications from the flu:
- pregnant women (any trimester)
- people aged 65 years and over
- people under 65 years of age with with certain chronic conditions, such as chronic heart disease, chronic liver disease, diabetes, cancer, asthma and COPD
- children aged 4 years or under who have been in hospital for respiratory illness or have a history of significant respiratory illness, including children aged 6–59 months (under 5 years) who were hospitalised with measles.
- Check with your doctor if you are uncertain about whether you qualify for a free flu vaccine.
The vaccination is also recommended (although may not be free) if you are in close contact with people with weakened immune systems, as these people may be less able to fight off the flu or are at high risk of complications from it. Frontline healthcare workers usually have the vaccine funded by their employer.
How is the flu vaccine given?
The vaccine is given by injection into a muscle, such as the muscle on your upper arm. If you have a condition that makes you bleed more easily than normal, it may be given as an injection underneath your skin. Babies and toddlers are given the injection on the side of their thigh.
Adults and children 9 years and older: Only one dose of the vaccine is needed to get protection for the season.
Children aged between 6 months and under 9 years: Two doses of the vaccine are needed, with the second dose given at least 4 weeks after the first. Children in this age group who have received a flu vaccine at any time in the past need only one dose.
After you get the flu vaccine, a trained healthcare professional will keep an eye on you for at least 20 minutes afterwards to make sure you don't have any reaction to the vaccination.