Immunization
Immunisation is a simple, safe and effective way of protecting children against certain diseases. The risks of these diseases are far greater than the very small risks of immunisation. This website will help you make a decision on your child’s immunisation based on the best available information at this time. If you have any questions about the information in this website, please discuss them with your local doctor or health clinic.
Immunisation protects children (and adults) against harmful infections before they come into contact with them in the community. Immunisation uses the body’s natural defence mechanism - the immune response - to build resistance to specific infections. Nine diseases can be prevented by routine childhood immunisation - diphtheria, tetanus, whooping cough, poliomyelitis (polio), measles, mumps, rubella, Haemophilus influenzae type b(Hib) and hepatitis B. All of these diseases can cause serious complications and sometimes death. Immunisation is given as an injection or, in the case of polio vaccine, taken as drops by mouth. Immunisation helps children stay healthy by preventing serious infections.
Immunisation and vaccination
Technically ‘vaccination’ is the term used for giving a vaccine - that is, actually getting the injection or swallowing the drops. ‘Immunisation’ is the term used for the process of both getting the vaccine and becoming immune to the disease as a result of the vaccine. Most people use the terms 'vaccination' and 'immunisation' interchangeably but their meanings are not exactly the same because immunity follows vaccination in most, but not all, cases. For the purposes of this site, we have always used the term ‘immunisation’ because this is the expression most commonly used in the community.
How does immunisation work?
All forms of immunisation work in the same way. When someone is injected with, or swallows, a vaccine, their body produces an immune response in the same way it would following exposure to a disease but without the person getting the disease. If the person comes in contact with the disease in the future, the body is able to make an immune response fast enough to prevent the person getting sick.
What is in vaccines?
Some vaccines contain a very small dose of a live, but weakened form of a virus. Some vaccines contain a very small dose of killed bacteria or small parts of bacteria, and other vaccines contain a small dose of a modified toxin produced by bacteria. Vaccines may also contain either a small amount of preservative or a small amount of an antibiotic to preserve the vaccine. 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 several 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. A child who has been given only one or two doses of diphtheria-tetanus-pertussis vaccine (DTPa) is only partially protected against diphtheria, pertussis (whooping cough) and tetanus, and may become sick if exposed to these diseases.
How long do immunisations last?
The protective effect of immunisations is not always lifelong. Some, like tetanus vaccine, can last up to 30 years, after this time, a booster dose may be given. Some immunisations, such as whooping cough, 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. Three doses of whooping cough vaccine protects about 85% of children who have been immunised, and will reduce the severity of the disease in the other 15% of children (who have also been immunised), if they do catch whooping cough. Booster doses are needed because immunity decreases over time. Three doses of hepatitis B vaccine protects over 95% of children.
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 the vaccine are needed. In the first months of life, a baby is protected from most infections 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.
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. Paracetamol might be required to help ease the fever and soreness. For more information, refer to Common side effects of immunisation and what to do about them. Other side effects are very rare but if they do occur, a doctor should be consulted immediately. Side effects of specific vaccines are described in The vaccines and the diseases they prevent.
Why should I have my child immunised?
There are two reasons for immunising everyone 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.
2. If enough people in the community are immunised, the infection can no longer be spread from person to person and the disease dies out altogether. This is how smallpox was eliminated from the world, and polio has disappeared from many countries.
The vaccines and the diseases they prevent
Diphtheria, tetanus and whooping cough
Diphtheria, tetanus and whooping cough are serious diseases that occur in children and adults. Combination vaccines that include DTPa (diphtheria-tetanus-acellular pertussis) give effective protection against these diseases.
Diphtheria
Diphtheria is caused by bacteria which are found in the mouth, throat and nose of an infected person. Diphtheria can cause a membrane to grow around the inside of the throat which can lead to difficulty in swallowing, breathlessness and suffocation. A powerful poison (toxin) is produced by the diphtheria bacteria and may spread throughout the body. The toxin may cause serious complications such as paralysis and heart failure. About 7% of people who contract diphtheria die from it.
Tetanus
Tetanus is an often fatal disease caused by a toxin made by bacteria present in soil and manure. You don’t catch tetanus from other people. Rather, the bacteria enter the body through a wound which may be as small and insignificant as a pinprick. Tetanus attacks the nervous system, causing severe muscle spasms, first felt in the neck and jaw muscles (lockjaw). The effects spread, causing breathing difficulties, painful convulsions and abnormal heart rhythms. Because of immunisation, tetanus is now rare in children in Australia but it still occurs in adults who have never been immunised against it or who have not had their boosters.
Whooping cough
Whooping cough, which is also known as pertussis, is a highly contagious disease caused by bacteria and is spread by coughing or sneezing. Whooping cough affects the air passages and can cause difficulty in breathing. Severe coughing spasms occur and between these spasms, the child gasps for breath causing the characteristic ‘whoop’ sound. Not all children get the ‘whoop’ and vomiting often follows a coughing spasm. The cough may last for months. Whooping cough is most serious in babies under 12 months of age, often requiring admission to hospital. Complications include convulsions, pneumonia, coma, inflammation of the brain, permanent brain damage and long-term lung damage. Around one in every 200 children under six months of age who catches whooping cough will die.
DTPa immunisation
Immunisation with DTPa vaccine is the best way to prevent diphtheria, tetanus and whooping cough. DTPa vaccine is a combination vaccine in which three vaccines are combined in one injection to prevent diphtheria, tetanus and whooping cough. Alternatively, these three vaccines are combined with hepatitis B vaccine. DTPa-containing vaccines contain a small amount of diphtheria and tetanus toxins which are modified to make them harmless, small parts of the pertussis bacteria, aluminium hydroxide (to increase the effectiveness of the vaccine) and a preservative (phenoxyethanol).
Possible side effects of DTPa immunisation
The recommended DTPa immunisation has few side effects, although some children may have mild fever and redness, soreness and swelling in the area where the injection was given. Mostly these side effects will settle without treatment but paracetamol may help to reduce fever and soreness at the injection site. In the past, concerns have been expressed about the possibility of whooping cough vaccine causing encephalitis (inflammation of the brain) and brain damage. The most careful studies show that there is not a proven link between DTPa vaccine and brain damage, and the risk is thought to be less than one in a million, if any at all. The very real risk of severe complications from the whooping cough disease is much greater than the risk of an extremely rare reaction following a DTPa immunisation.
If none of the children in a child care centre of 150 children were immunised, and a whooping cough outbreak occurred, about 135 children would come down with the disease. On average, one child would get encephalitis (inflammation of the brain) as a result of the disease. If every child in the centre was immunised correctly with four doses of DTPa, possibly one child at the centre every 170 years could get encephalitis associated with the immunisation.
Following the introduction of polio vaccines there has been a dramatic decrease in polio infection. However, it is still important to have your child immunised against polio.
Children still need to be immunised against polio, even though cases do not occur here. Polio may cause mild symptoms or very severe illness. It is a gastrointestinal virus which causes fever, vomiting and muscle stiffness, and can affect the nerves and cause permanent crippling. Polio can paralyse the breathing and swallowing muscles, leading to death. About 5% of people hospitalised with polio die from it, and about half of those who survive suffer permanent paralysis.
Polio immunisation
Oral polio vaccine (OPV or Sabin) is given as drops by mouth. Several doses are needed to provide good protection. The vaccine contains small amounts of three types of live polio viruses which have been altered so they do not cause the disease, and a very small amount of an antibiotic (neomycin). The polio vaccine virus is present in faeces for approximately six weeks following immunisation with OPV. The contacts of a recently vaccinated baby need to ensure strict personal hygiene, particularly washing their hands after changing the baby's nappies. A child should not be given OPV if he or she has, or lives with someone who has, a disease such as leukaemia or HIV/AIDS or is on medication which causes lowered immunity. There is a small risk of illness caused by polio vaccine virus in these people. Inactivated polio vaccine (IPV or Salk), which is given by injection, is available for these people and those living with them.
Possible side effects of polio immunisation
A few people will have mild symptoms such as headache, muscle pains and mild diarrhoea after receiving OPV. Very rarely (about one in 2.5 million doses), OPV has been reported to cause paralysis in a person who is immunised or who has been in close contact with a recently immunised person.
Measles, mumps and rubella (German measles) are all serious viral diseases. A combined measles-mumps-rubella (MMR) vaccine is used to protect children against these diseases.
Measles
Measles is a serious, highly contagious viral illness which causes fever, rash, runny nose, cough and conjunctivitis. Complications following measles can be very dangerous, and pneumonia occurs in 4% of cases. Approximately one child in every 2,000 who contracts measles will develop inflammation of the brain (encephalitis). For every 10 children who contract measles encephalitis, one will die and up to four will have permanent brain damage. Measles has caused more deaths in Australia in the past 15 years than diphtheria, whooping cough and rubella combined. A very serious but rare illness called subacute sclerosing panencephalitis (SSPE) can occur in children several years after a measles infection. SSPE is a disease which rapidly destroys the brain and always results in death. SSPE develops in about one in 25,000 cases of measles.
Young adults between the ages of 18 and 30 years have also been identified as an 'at-risk' group for measles. The reasons for this group having a higher susceptibility to measles is because:
- they are too old to have been recipients of the two-dose MMR vaccination program that was introduced in 1994, and some will not have received a single dose; and
- previous measles control initiatives, including the Measles Control Campaign, and the two-dose MMR policy, appear to have raised levels of immunity in younger age groups to a point where sustained transmission of measles is unlikely to occur, thereby increasing the age of those infected during an outbreak.
It is anticipated that free MMR vaccine will be available between March and June 2001 for young adults.
Mumps
Mumps is a viral disease which causes fever, headache and inflammation of the salivary glands. Occasionally it causes an infection of the membranes covering the brain (meningitis) but permanent effects are rare. In as many as five per 1,000 patients it can cause inflammation of the brain (encephalitis). Mumps can also cause permanent deafness. About one in five adolescent or adult males who contracts mumps develops painful inflammation and swelling of the testicles. While the person with this condition usually recovers completely, on rare occasions it may cause infertility.
Rubella
Rubella, which used to be called German measles, is usually a mild disease of childhood but it can also affect teenagers and adults. The usual symptoms of rubella are a slight fever, swollen glands, joint pain and a rash which appears on the face and neck and lasts for two or three days. Recovery from rubella is almost always speedy and complete. The most dangerous form if rubella infection is congenital rubella, where infection during the first 20 weeks of pregnancy can result in devastating abnormalities in the newborn baby. Deafness, blindness, heart defects and mental retardation can occur. Rubella is highly contagious. The best way to protect expectant mothers and their babies from rubella is to make sure that all women have been immunised before they become pregnant, and to immunise all children to stop the spread of infection.
Measles-mumps-rubella (MMR) immunisation
Children should be first immunised against measles, mumps and rubella at 12 months of age. The vaccine can also be given to older children and adults, and is very effective. The combination measles-mumps-rubella (MMR) vaccine protects children against all three diseases. Children should receive a second dose of MMR vaccine at 4 years of age. Women of child bearing age, and especially those considering pregnancy, should have a blood test for rubella, as the immunisation they received as a teenager may have worn off. If rubella antibody levels are low, these women should receive MMR vaccine. Women should not receive the vaccine if they are pregnant or might become pregnant within two months. The MMR vaccine contains small amounts of reduced strength live measles, mumps and rubella viruses, and a small amount of an antibiotic (neomycin).
Possible side effects of MMR immunisation
Reactions to MMR immunisation are much less frequent than the complications of natural measles. The most common reaction is feeling unwell and having a low grade fever, possibly with a rash, occurring 5 to 12 days after immunisation. Children who develop the rash during this time are not infectious to others. The fever can be reduced with appropriate doses of paracetamol. Occasionally children will develop a mild swelling of the salivary glands about three weeks after the immunisation because of the mumps component of the vaccine. More serious reactions are rare. About one in 30,500 children develops thrombocytopenia (bruising or bleeding). If encephalitis (inflammation of the brain) occurs at all following MMR immunisation, it is very rare - probably at a rate of one in a million doses or less. Subacute sclerosing panencephalitis (SSPE) is prevented by immunisation. The risks of serious complications after catching measles, mumps or rubella, are much greater than the very small risks of the MMR immunisation.
If every child in a school of 500 children had not been immunised and an outbreak of measles occurred, nearly every student would come down with measles. Pneumonia would occur in 20 children. There is a 25% chance that one child in the school would develop encephalitis (inflammation of the brain) as a result of measles. If every child in the school was immunised correctly with MMR vaccine, on average there would be one case of encephalitis every 2000 years caused by the immunisation.
Haemophilus influenzae type b (Hib)
Hib was the most frequent cause of life threatening infection in children under five years of age before the introduction of Hib vaccines. Despite its name, it is not related in any way to influenza (‘the flu’). It may cause infection of the membranes covering the brain (meningitis), swelling in the throat which can block breathing (epiglottitis), pneumonia, joint infection or infection of the tissue under the skin, usually on the face (cellulitis). Both meningitis and epiglottitis can develop quickly and if left untreated, can rapidly cause death.
Hib immunisation
Several doses of Hib vaccine are required to protect a child against Hib. The first dose is normally given at two months of age. However, children up to the age of five years who were not immunised as babies can be given Hib vaccine. Older children do not need as many doses of Hib vaccine. Hib infection is rarely a problem in children over five years of age. For children born after 1 May 2000, the recommended Hib vaccine in Australia is PRP-OMP (PedvaxHIB). This vaccine contains a small amount of part of the Hib bacteria attached to a protein which stimulates the immune response. The PRP-OMP (PedvaxHIB) vaccine also contains a small amount of an aluminium salt. For children born before 1 May 2000, HbOC (HibTITER) which appears on the previous Immunisation Schedule, will continue to be the recommended vaccine. This vaccine also contains a small amount of a part of the Hib bacteria attached to a protein. PedvaxHIB is a three dose schedule and HbOC is a four dose schedule. The Hib vaccine may be combined with hepatitis B vaccine.
Possible side effects of Hib vaccine
Hib vaccines are very safe. Mild swelling, redness and pain at the injection site have been reported in up to 5% of children who receive a Hib vaccine. Fever and irritability are uncommon. More serious reactions to Hib vaccines have not been reported.
It is caused by a virus that affects the liver. Babies that get this disease may only have mild symptoms, or have no symptoms at all. However, many of these babies will go on to carry the virus in their bloodstream for many years and may then be able to pass it on to other people. As many as 25% of such hepatitis B carriers may develop liver cancer or liver failure later in life.
The hepatitis B virus is present in infected body fluids including blood, saliva and semen. Babies whose mothers have hepatitis B are at very high risk of being infected with the disease at birth. Other ways in which hepatitis B can be spread are by blood to blood contact, sharing of syringes, sexual contact, and contaminated instruments such as those used for body piercing. Immunisation has proven over many years to be a safe and cost effective way of preventing this disease.
Hepatitis B immunisation
For babies the first dose of hepatitis B is given soon after birth, the second at 2 months of age, the third at 4 months of age and the final dose at either 6 or 12 months of age to provide full protection. The last three doses of hepatitis B are given in combination vaccines, which means getting the vaccine does not mean extra injections. For adolescents who have not received the hepatitis B vaccine the first immunisation is given at 10 to 13 years of age, the second dose one month later and the third dose 5 months after the second. The vaccines contain a modified part of the hepatitis B virus. They are produced in yeast cells and are free of association with animal or human blood or blood products. The hepatitis B vaccine contains a small amount of aluminium salt. The monovalent Hepatitis B vaccine given at birth (to adolescents following the previous schedule) may contain thiomersal (a mercury containing preservative). However, there are two thiomersal-free vaccines now available.
Possible side effects of hepatitis B immunisation
Most side effects of hepatitis B vaccine are minor and disappear quickly. Soreness at the injection site may occur, as may mild fever, nausea, feeling unwell and joint pain. More serious side effects are extremely rare.
Common misconceptions for missing immunisation
Your child should still be immunised, even if he or she:
- has a family history of any reactions following immunisation;
- has a family history of convulsions;
- has had whooping cough, measles, rubella or mumps infection;
- is premature (immunisation should not be postponed);
- has a stable neurological condition such as cerebral palsy or Down's syndrome;
- has been in contact with an infectious disease;
- has asthma, eczema, hay fever or 'snuffles';
- is on treatment with antibiotics;
- is on treatment with locally-acting (inhaled or low-dose topical) steroids;
- has a pregnant mother;
- is being breast-fed;
- was jaundiced after birth;
- is over the age recommended in the standard vaccination schedule;
- has had recent or imminent surgery;
- is of low weight but otherwise healthy;
- has been treated with replacement corticosteroids.
If you want more information on this, please consult your local doctor or health clinic staff.
Common side effects of immunisation & what to do about them
Many children experience minor side effects following immunisation. Most of these only last a short time and the child recovers without any problems. A child needs comforting if side effects occur and you can reduce the side effects by following a few simple guidelines. Listed below are common side effects of each immunisation and what you can do about them.
DTPa (diphtheria-tetanus-pertussis vaccine)
Common reactions
The following may occur soon after immunisation and may last up to two days:
- low grade fever
- being grizzly, unsettled and generally unhappy
- soreness, swelling and redness in the area where the injection was given
What to do
- Give extra fluids to drink
- Do not overdress the baby if hot
- Give paracetamol to lower fever if needed
MMR (measles-mumps-rubella vaccine)
Common reactions
Discomfort at the injection site may occur. The following may occur five to twelve days after immunisation and last less than 48 hours:
- low grade fever
- faint rash (not infectious)
- head cold and/or runny nose
- cough and/or puffy eyes
- stiff neck or joint pain
- swelling of the facial glands may occur about three weeks after immunisation
What to do
- Give extra fluids to drink
- Do not overdress the child if hot
- Give paracetamol to lower fever if needed
OPV (oral poliomyelitis vaccine)
Possible reactions
The following reactions are uncommon and if they occur it is soon after the immunisation:
- Diarrhoea
- Headache and/or muscle pains
What to do
- Give extra fluids to drink
- Give paracetamol to relieve aches/pains if needed
Hib (Haemophilus influenzae type b) vaccine
Possible reactions
The following reactions are uncommon and if they occur, it is soon after the immunisation:
- Low grade fever
- Soreness, redness and swelling in the area where the injection was given
What to do
- Give extra fluids to drink
- Do not overdress the baby if hot
- Give paracetamol to lower fever if needed
Hepatitis B vaccine
Possible reactions
The following reactions are uncommon and if they occur, it is soon after the immunisation:
- Low grade fever
- Nausea, feeling unwell and joint pain
- Soreness, redness and swelling in the area where the injection was given
What to do
- Give extra fluids to drink
- Do not overdress the baby if hot
- Give paracetamol to lower fever if needed
Speak to your doctor or health clinic staff if you are worried about such reactions.
Paracetamol doses for children to reduce side effects:
The routine use of paracetamol at the time of immunisation is no longer recommended, due to the use of better vaccines with fewer side effects. However, speak with your doctor, pharmacist or nurse regarding the use of paracetamol if you are concerned about side effects like fever and being unsettled. When MMR is given a fever may occur about 5 to 12 days later, and paracetamol should be given then. Children who have had a fit or have epilepsy should be given paracetamol before and for 48 hours after immunisation to reduce the chance of fever. Doses of paracetamol should not be given closer than four hours apart and the maximum number of doses you should give in 24 hours is six. Paracetamol for children comes in different strengths and you should check the strength on the label. The recommended dosage for children following immunisation is 15 milligrams (mg) per kilogram of the child's weight per dose. The dose recommended on the bottle is usually slightly smaller than this.
Please note, the prolonged use of paracetamol without medical supervision could be harmful.
What to tell the doctor or nurse when taking your child for an immunisation:
Before you have your child immunised, tell the doctor or nurse if your child:
- is unwell today;
- has had a severe reaction following any vaccine;
- has any severe allergies;
- has had a live vaccine within the last month (including tuberculosis and live virus vaccines such as MMR, oral poliomyelitis or yellow fever), or an injection of immunoglobulin, or a whole blood transfusion in the last three months;
- has a disease which lowers immunity (eg. leukaemia, cancer, HIV/AIDS) or is having treatment which lowers immunity (eg. steroid medicines such as cortisone and prednisone, radiotherapy and chemotherapy);
- lives with someone who has a disease which lowers immunity, or lives with someone who is having treatment which lowers immunity;
- has a medical condition affecting the brain or spinal cord (eg. spina bifida);
- is living with someone who is not immunised (only for OPV).
Your doctor or health clinic staff should know about these conditions because your child may need to be immunised differently. You should also take your child's Personal Health Record with you when having your child immunised.