About immunisation
State and Territory information:
What is immunisation?
Immunisation & vaccination
How does immunisation work?
What is in vaccines?
How long do immunisations take to work?
How long do immunisations last?
Is everyone protected from disease by immunisation?
Why do children get so many immunisations?
What are the side effects of immunisation?
Why should children be immunised?
What is immunisation?
Immunisation can protect people against harmful infections, which can cause serious complications, including death.Immunisation uses the body’s natural defence mechanism - the immune response - to build resistance to specific infections.
These diseases, which can be prevented by routine childhood immunisation, are included in the National Immunisation Program Schedule (NIPS):
chickenpox (varicella) | diphtheria | Haemophilus influenzae (type b (Hib) | hepatitis A* | hepatitis B | measles | meningococcal C | mumps | pneumococcal | polio (poliomyelitis) | rotavirus | rubella | tetanus| whooping cough (pertussis)
*Indigenous children in Queensland, Northern Territory, Western Australia and South Australia are protected against hepatitis A.
In adulthood, these diseases can be prevented by immunisation which is funded under the Immunise Australia Program.
influenza (flu) | pneumococcal | Q fever
Immunisation and vaccination
- Vaccination means having a vaccine - that is actually getting the injection.
- Immunisation means both receiving a vaccine and becoming immune to a disease, as a result of being vaccinated against that disease.
The term 'immunisation' is used in this website, as it's most commonly used in the community.
How does immunisation work?
All forms of immunisation work in the same way.When a person is vaccinated, their body produces an immune response in the same way their body would after exposure to a disease, but without the person suffering any symptoms of the disease. When a person comes in contact with that disease in the future, their immune system will respond fast enough to prevent the person developing the disease.
What is in vaccines?
Vaccines contain either:- a very small dose of a live, but weakened form of a virus;
- a very small dose of killed bacteria or virus or small parts of bacteria; or
- a small dose of a modified toxin produced by bacteria.
Some vaccines may also contain a small amount of an aluminium salt which helps produce a better immune response.
How long do immunisations take to work?
In general, the normal immune response takes approximately two weeks to work. This means protection from an infection will not occur immediately after immunisation.Most immunisations need to be given several times to build long lasting protection. For example, a child who has been given only one or two doses of diphtheria-tetanus-pertussis vaccine (DTPa) is only partially protected against diphtheria, whooping cough (pertussis) and tetanus, and may become sick if exposed to these diseases.
How long do immunisations last?
The protective effect of immunisations is not always for a lifetime. Some, like tetanus vaccine, can last up to 30 years, after which, a booster dose may be given. Some immunisations, such as whooping cough (pertussis), give protection for about five years after a full course.Is everyone protected from disease by immunisation?
Even when all the doses of a vaccine have been given, not everyone is protected against the disease.Measles, mumps, rubella, tetanus, polio and Hib vaccines protect more than 95% of children who have completed the course.
One dose of meningococcal C vaccine at 12 months protects over 90% of children.
Three doses of whooping cough (pertussis) vaccine protects about 85% of children who have been immunised, and will reduce the severity of the disease in the other 15%, if they do catch whooping cough.
Booster doses are needed because immunity decreases over time.
Why do children get so many immunisations?
A number of immunisations are required in the first few years of a child’s life to protect the child against the most serious infections of childhood. The immune system in young children does not work as well as the immune system in older children and adults, because it is still immature. Therefore more doses of vaccine are needed. In the first months of life, a baby is protected from most infectious diseases by antibodies from her or his mother, which are transferred to the baby during pregnancy. When these antibodies wear off, the baby is at risk of serious infections and so the first immunisations are given before these antibodies have gone.Another reason why children get many immunisations is that new vaccines against serious infections continue to be developed. The number of injections is reduced by the use of combination vaccines, where several vaccines are combined into one shot.
What are the side effects of immunisation?
Common side effects of immunisation are redness and soreness at the site of injections and mild fever. While these symptoms may concern you and upset your child at the time, the benefit of immunisation is protection from the disease. More serious reactions to immunisation are very rare.Paracetamol can be used to help ease the fever and soreness, but care needs to be taken to follow the dosage instructions.
For more information, refer to Common side effects of immunisation and what to do and Immunisation: myths and realities.
Other side effects are very rare but if they do occur, a doctor should be consulted immediately.
Why should children be immunised?
There are two reasons for immunising every child in Australia:1. Immunisation is the safest and most effective way of giving protection against the disease. After immunisation, your child is far less likely to catch the disease if there are cases in the community. The benefit of protection against the disease far outweighs the very small risks of immunisation.
Page last modified: 08 April, 2008