Vaccination is treatment with a vaccine (usually by injection) that helps the immune system prepare to fight a future infection.

Vaccines often contain tiny amounts of dead or weakened viruses or bacteria, or parts of them.  Some vaccines contain inactivated toxins that are produced by disease-causing bacteria. 

Once in the body, the immune system will react to the vaccine without you actually experiencing the disease. This reaction also means that if the same disease-causing organism comes in contact with your immune system in the future, your body is able to quickly make antibodies that can stop the disease from making you sick. 

Some vaccines need to be given more than once (ie, a ‘booster’ vaccination) to make sure the immune system can overcome a real infection in the future. Some vaccines, like the seasonal influenza vaccine, are only protective for a short period of time, because the organism itself can change over time. This is why it is recommended that a person gets the current influenza vaccine every year.

Vaccines and immunisation useful links

• National Immunisation Program website
  
• The Australian Immunisation Handbook
  
• National Centre for Immunisation Research and Surveillance
  
• Sharing Knowledge About Immunisation (SKAI)
• Travel vaccinations - Smartraveller.gov.au

Vaccination is when a vaccine is administered to you (usually by injection).

Immunisation is what happens in your body after you have the vaccination. The vaccine stimulates your immune system so that it can recognise the disease and protect you from future infection (ie, you become immune to the infection).

‘Vaccination’ and ‘immunisation’ are often used interchangeably but their meanings are not exactly the same.

All medicines, including vaccines, are continually monitored for safety and potential side effects.

The chance that a vaccine will cause you or your child serious harm is extremely small and being vaccinated is less harmful than the alternative of getting the disease.

You, or your child, should have all the recommended vaccines at the recommended times, unless your health professional advises you not to have them for medical reasons. For example, if you have a weakened immune system due to another infection or medicines that you are taking to suppress your immune system.

Before you, or your child, has any vaccination, always let your doctor know if you or you child have any allergies, or have had any reactions to a vaccine in the past. This is because very rarely, some people may be allergic to some part of a vaccine.

What are the side effects of vaccines?

Most of the side effects associated with vaccines are minor, and usually go away within a few days.

The most common* side effects of almost all vaccines are:

• fever (a temperature higher than 38.5°C)
• redness, swelling and tenderness at the injection site
• headache, tiredness and nausea.

Vomiting, diarrhoea, and muscle or joint pain, occur less frequently
*Common: 1 to 10 in every 100 people will experience these side effects.

Who can I ask about side effects?

If you’re concerned that you or your child may have had side effects related to a vaccine, seek medical advice. To report and discuss possible side effects, call the Adverse Medicines Events (AME) Line on 1300 134 237 from anywhere in Australia (Monday–Friday, 9am–5pm AEST).

Fevers are common in young children, especially after a vaccination, but they are usually mild. A fever doesn’t necessarily mean your child has a serious illness. In fact, a fever helps the body's immune system to fight infection.

What will help my child’s fever?

If your child has a fever:

• let them rest
  
• dress them lightly, but ensure they’re not cold either
  
• give them lots of clear fluids to drink (eg, small amounts of water or diluted fruit juice)
  
• if your child is younger than 6 months give them extra cooled pre-boiled water, breast milk, or bottles of formula.
  

A fever helps the body's immune system to fight infection, so there is no need to treat your child's fever with a medicine (paracetamol or ibuprofen), unless the fever is making them uncomfortable or miserable.

When should I treat a fever with a medicine?

If your child has a temperature higher than 38.5°C after a vaccination (or any other time) and this is making them uncomfortable or miserable, paracetamol or ibuprofen can be given to help ease any discomfort.

Paracetamol or ibuprofen might reduce a child’s temperature, but the aim is not to bring their temperature back to normal. A fever helps the body's immune system to fight infection.

Only give your child paracetamol or ibuprofen at the doses and times your doctor or pharmacist recommends, or read the instructions on the medicine label. Do not give more than the maximum recommended dose and don’t give it for longer than 2 days without seeking medical advice.

Beware of ‘double dosing’ - paracetamol is a common ingredient in many medicines, so it is important to check the active ingredients on the label of any other medicines to avoid ‘doubling up’ and giving your child other medicines that also contain paracetamol.

Fever and seizures

Some children can have a fit or seizure if their temperature rises suddenly. This is called a febrile convulsion. Regardless of vaccination, by the age of 5 years, around 3% of all children will have had a febrile convulsion. While these convulsions might alarm you, they do not usually cause any long-term health effects.

Talk to your doctor if you are concerned about febrile convulsions. Seek medical advice immediately if your child has had one for the first time, or it lasts more than 5 minutes.

For more information on febrile seizures, read this fact sheet.

What not to do for a fever

Sponging your child with lukewarm (tepid) or cold water or a damp cloth is not recommended. This can actually increase their body temperature by narrowing your child’s blood vessels in order to keep their body warm.

Unless your child has a history of seizures, giving them paracetamol at the time of vaccination to prevent fever is not recommended. This is because a fever is generally not harmful — it actually helps the body to fight infection.

Measles, mumps and rubella (German measles) are all infectious diseases caused by viruses. These diseases can cause serious complications — especially rubella infection in unborn children — and can sometimes be fatal. The MMR vaccine is a combination vaccine that protects you against all three of these diseases.

Measles is a very infectious disease. It is spread when saliva droplets containing the virus are breathed in by others. This can happen when someone with the infection sneezes or coughs.

You can catch measles if you are in the same room as someone with the infection, and for up to 2 hours after someone with measles has left the room (eg, in a doctor’s waiting room or an Accident and Emergency department).

Complications of measles include ear and lung infections. One in every 1,000 children who gets measles will get encephalitis (inflammation of the brain). Children with encephalitis are at risk of brain damage or death.

Mumps affects the salivary glands. It is spread when saliva droplets containing the virus are breathed in by others. This can happen when someone with mumps sneezes or coughs. The mumps virus can also spread by direct contact with infected saliva.

Complications of mumps include:

• hearing loss due to nerve damage
  
• encephalitis (inflammation of the brain) (1 in 200 people)
  
• infections of the ovaries, pancreas, liver and heart
  
• serious infection of the testicles that can cause sterility in men (this is rare).
  

Rubella (German measles) is spread when saliva droplets containing the virus are breathed in by others. This can happen when someone with the infection sneezes or coughs.

Complications of rubella infection include encephalitis (inflammation of the brain) and low levels of white cells and platelets in the blood, but these are rare.

The most important reason for vaccinating against rubella is to protect women and their unborn children from exposure to the disease. Women who become infected with rubella in the first 20 weeks of pregnancy are not only at risk of miscarriage, but are very likely to pass it on to their unborn baby causing a condition called congenital rubella syndrome. Congenital rubella syndrome can cause the baby to be born with one or more of the following defects:

• brain damage
  
• blindness
  
• deafness
  
• heart defects.
  

Who should be vaccinated?

Children - MMRV can be given to children who are 18 months old who have been vaccinated with the MMR vaccine at 12 months. The vaccinations are free for all children in this age group as part of the National Immunisation Program Schedule. 

Adults - all adolescents and adults who have not been vaccinated against measles, mumps or rubella, or who have not received two doses of a measles-containing vaccine, should be vaccinated with the MMR vaccine. If you are unsure, check with your doctor about whether you should be vaccinated. Adults who need to have the MMR vaccine can be vaccinated at their own cost.

Pregnant women - the MMR vaccine is not given to women who are pregnant. Pregnant women who think they have rubella, or think they have been exposed to rubella, should seek medical advice as soon as possible.

Women of childbearing age - if you have not had the MMR vaccine, you should be vaccinated at least 28 days before becoming pregnant, or immediately after they have given birth. If you have just been vaccinated with MMR, you should avoid falling pregnant for 28 days after your vaccination.

The MMR vaccine does not cause autism.

The flu vaccine protects you from getting flu, a common illness caused by the influenza viruses (A and B). The infection affects the nose, throat, bronchi and, occasionally, the lungs.

Influenza viruses are always changing. So, each year the flu vaccine also changes to contain the strains of virus mostly likely to be around during the current flu season.

To stay protected, it is recommended that you have a vaccination every year.

The flu virus can spread very easily. When an infected person sneezes or coughs, they release droplets containing the flu virus into the air. These droplets can be breathed in by others or land on a surface that someone can touch.

Who should be vaccinated?

Annual flu vaccinations are recommended for anyone over the age of 6 months.

You can read more about influenza vaccines and children on this webpage.

Vaccination is strongly recommended if you have an existing medical condition that could become worse because of an influenza infection.

Pregnant women can receive a flu vaccination at any stage during pregnancy. Have the flu vaccine in autumn if you will be, or are planning to be, pregnant during winter.

Women who are breastfeeding can receive a flu vaccination.

You can read more about getting vaccinated on this webpage.

Who is eligible for free flu vaccinations?

Every year, many Australians can receive a free flu vaccine as part of the National Immunisation Program. Your health professional will know if you are eligible. Eligible people include:

• people aged 65 years and over
• pregnant women
• all Aboriginal and Torres Strait Islander people aged 6 months and over
• all people with certain medical conditions, including severe asthma, heart disease or diabetes
• some healthcare workers (different states and territories have different criteria).

You can read more about the National Immunisation Program on this webpage.

Different vaccines are available for different age groups. Make sure the vaccination provider knows the age of the person getting vaccinated, so they can give the correct dose and brand.

It is important to note that while the flu vaccine may be free for you, your provider may still charge a consultation fee.

What else can stop the flu spreading?

Vaccination is the most effective way of reducing the impact of flu in the community. There are other actions that people can take to help stop the spread of this contagious virus. These include:

• washing hands regularly, preferably with soap and water, before and after touching others, and before handling food
• covering your nose and mouth with tissues, or your elbow, when you sneeze or cough
• throwing used tissues away immediately
• not sharing personal items such as cups, plates and cutlery
• staying at home when you are sick.

You can catch typhoid by eating or drinking contaminated food or water. Typhoid symptoms vary but can include fever, feeling tired and unwell, abdominal problems and coughing.

Typhoid is common in developing countries including India, most countries in Southeast Asia, and Papua New Guinea. Anyone travelling to a country where typhoid is present, and who might be at higher risk of infection, should be vaccinated.

There are two types of typhoid vaccine, one is injected and the other is given by mouth (orally). Neither vaccine provides protection for longer than 3 years, so if you will be travelling to a country where typhoid is present, and it has been about 3 years since your last vaccination, you may need to be revaccinated.

Pregnant women - tell your doctor if you are pregnant or could be pregnant because some typhoid vaccines should not be given to pregnant women (ie, an oral live attenuated vaccine).

If you are pregnant and you have to travel to a country where typhoid is present and water quality is poor, your doctor may recommend vaccination with the injectable typhoid vaccine, as you will be at increased risk of infection.

Women who are breastfeeding - there is no known risk to your baby if you are vaccinated with the typhoid vaccine while you are breastfeeding.

The tetanus vaccine protects you against the toxin (poison) produced by the Clostridium tetani bacteria that cause tetanus (also known as lockjaw).

The bacteria grow in soil and faeces (eg, manure), but can exist anywhere in the environment. If you have a cut or wound on your hand for example, the wound can become contaminated with the bacteria, which then enter your blood stream. You can’t catch tetanus from other people.

Tetanus can be fatal. The toxin affects the nerves in your brain and spinal cord (the central nervous system). This in turn causes stiffness in your neck, shoulder and jaw muscles (lock jaw), breathing difficulties and difficulty talking, painful muscle spasms and an abnormal heart beat.

Who should be vaccinated?

The tetanus vaccine is given as part of a combined vaccine. There are three vaccinations and two booster vaccinations given at different ages.

Even though tetanus disease is rare in Australia, it’s important to make sure that you have been vaccinated, as you can get infected even if you have a relatively small cut or wound (eg, when gardening). Tetanus infections mainly happen in older people who have never been vaccinated or were vaccinated a long time ago. A complete course of vaccinations will protect you against infection for many years.

Children - as part of the National Immunisation Program, a combined vaccine is given free to all children at ages 6 weeks to 2 months, at 4 months and again at 6 months of age. Two booster vaccinations are recommended at 18 months and 4 years of age. Older children are usually given an additional booster vaccination at 11 to 13 years.

Adults - your doctor may recommend having a tetanus-containing booster vaccination if you are 50 years or older and have not had one in the previous 10 years, if you have been injured, or before travelling. Ask your doctor for advice.

Pregnant women - the tetanus vaccine can be given to pregnant women. There is no known risk to your unborn baby.

Women who are breastfeeding - in general, there is no known risk to your baby if you are vaccinated with any vaccine – except the yellow fever vaccine – while you are breastfeeding.

Whooping cough can be a serious respiratory tract infection that is very easily spread (highly contagious). If left untreated, it can progress from an upper respiratory tract infection (in the nose, throat and windpipe) into a lung infection (pertussis pneumonia). Children with whooping cough may need to be hospitalised and can die from the infection.

Whooping cough is spread through droplets in the air that contain the bacteria. When someone with the infection sneezes or coughs, these droplets can be breathed in by others, or transferred to anyone who may touch a surface contaminated with the bacteria.

Whooping cough usually starts off with cold-like symptoms, and develops into a cough. A bout of coughing is often followed by a deep intake of breath making the characteristic ‘whoop’ sound suggested by the name. The cough can last for a few months. A serious complication of whooping cough is a lack of oxygen to the brain (hypoxic encephalopathy) that can lead to brain damage.

Who should be vaccinated?

Whooping cough can affect anyone who has not been vaccinated, but children younger than 6 months are at the greatest risk of severe infection as they won’t have had their full set of vaccinations, and will not be fully immune.

It is important that people who care for young infants (eg, parents and grandparents) also have a whooping cough vaccine, to prevent them passing on the infection to young children who are not fully immune.

Immunity to whooping cough decreases with time so it’s important that you and your child have all the recommended booster vaccinations. 

Children in Australia are vaccinated against whooping cough in a combined vaccine given as a single injection. There are four vaccinations given free at different ages as part of the National Immunisation Program schedule.

Adults - the body’s immunity to whooping cough infection will reduce with time (within 6-10 years), so a booster dose of the vaccine is recommended for adults who are:

• planning a pregnancy
  
• at risk of whooping cough infection (eg, healthcare workers)
  
• in contact with young children (eg, grandparents, and childcare workers)
  
• 65 years or older and who have not had a whooping cough booster in the previous 10 years.
  

The vaccination for adults is not funded by the National Immunisation Program.

Pregnant women - the whooping cough vaccine can be given to pregnant women during the third trimester of pregnancy if they are at risk of infection.

Women who are breastfeeding can be given the vaccine. There is no known risk to your unborn baby if you have the vaccination.

This vaccine protects you from getting rabies and Australian bat lyssavirus (ABLV), a closely related disease. Both diseases are caused by viruses.

Although rabies does not occur in Australia, it does occur in other countries. People travelling to Bali and other popular destinations in Asia, Africa and Central and South America, should discuss rabies vaccination with their doctor before travelling.

Rabies and ABLV is spread in the saliva of animals (eg, dogs and monkeys) or bats infected with the virus. The virus usually enters the body when you are bitten by an infected animal. It travels in the bloodstream from the wound to the brain, where it causes swelling (inflammation), and the characteristic symptoms of rabies that usually appear 3–8 weeks after being infected. 

Initial symptoms include appetite loss, fever, muscle aches (myalgia), tiredness, cough, sore throat, headache, anxiety, agitation, nausea and vomiting. Later symptoms include hyperactivity, disorientation, excited behaviour, sensitivity to air (aerophobia) and fear of drinking water (hydrophobia), and salivating excessively. The ABL virus causes paralysis, delirium, convulsions and death. Both infections are almost always fatal if symptoms develop.

Vaccines containing inactivated rabies virus are available to prevent these diseases. In Australia, you will only be given the vaccine if you have been in close contact with, or bitten by, a bat.

Who should be vaccinated?

The rabies vaccine is usually only given to people who are at risk of the infection, including people:

• travelling to, and staying for more than 1 month in, places where rabies is present
  
• whose occupation means that they may come into contact with bats (eg, bat handlers, vets and wildlife officers)
  
• people who work with animals in places where rabies is present (eg, vets and wildlife officers)
  
• people who work on rabies and bat lyssavirus in a laboratory.
  

Adults and children who are travelling to places where rabies is present should avoid close contact with wild and domestic animals (including bats). If you or your child is bitten by an animal seek medical attention immediately.

If you have recently been exposed to rabies, or think you may have been (eg, due to an animal bite), you should be vaccinated. Even if you have been vaccinated in the past you may need additional vaccinations if you have been bitten.

Pregnant women - your doctor may recommend that you have the rabies vaccination if you are pregnant, considered at risk of infection and you have to travel to countries where rabies is present.

Women who are breastfeeding - if you’re breastfeeding and you are travelling to countries where rabies is present, vaccination is recommended. There is no known risk to your baby if you are vaccinated with the rabies vaccine while you are breastfeeding.

Vaccine common side effects - between 1 and 10 in every 100 people may experience these

Bacillus Calmette-Guérin (BCG) vaccine for tuberculosis (TB)

• An ulcer at the injection site (2 to 6 weeks after the vaccination)
• Swollen glands

Chickenpox (varicella zoster)

• Soreness, redness and swelling at the injection site
• A lump at the injection site; this generally disappears after a few weeks and does not need treatment
• Fever (a temperature of 38.5°C or higher)
• A mild rash at the injection site 5 to 26 days after vaccination, and sometimes on other parts of the body

Cholera

• Mild stomach and gut (gastrointestinal) problems
• Diarrhoea
• Headach

Combined diphtheria, tetanus and whooping cough (pertussis)

• Fever (a temperature of 38.5°C or higher)
• Redness, swelling and tenderness at the injection site
• A lump at the injection site; this generally disappears after a few weeks and does not need treatment
• Children may cry and feel generally unwell (malaise)
• Tiredness or drowsiness

Haemophilus influenzae type b (Hib)

• Pain, redness, and swelling at injection site (injection site reactions become milder with subsequent doses)
• Fever (a temperature of 38.5°C or higher)
• Irritability, crying
• Drowsiness
• Vomiting

Hepatitis A

• Redness, swelling and pain at the injection site
• Fever (a temperature of 38.5°C or higher)
• Tiredness
• Headache
• Feeling generally unwell (malaise)
• Nausea
• Diarrhoea

Hepatitis B

• Redness, swelling and pain at the injection site
• Fever (a temperature of 38.5°C or higher)
• A lump at the injection site; this generally disappears after a few weeks and does not need treatment

Human papillomavirus (HPV)

• Fever (a temperature 38.5°C or higher)
• Mild headache
• Mild nausea
• Muscle or joint pain
• Tiredness

Influenza (flu)

• Fever (a temperature of 38.5°C or higher)
• Muscle tenderness or weakness (myalgia)
• Soreness, redness and swelling at injection site
• A lump at the injection site; this generally disappears after a few weeks and does not need treatment

These side effects may last 1 to 2 days after the vaccination. Side effects may be more severe in children who are younger than 5 years old (compared with older children and adults).

Japanese encephalitis

• Soreness, redness and swelling at the injection site
• Fever (a temperature of 38.5°C or higher)
• Muscle aches (myalgia)

Measles, mumps and rubella (MMR)

• Fever (a temperature of 38.5°C or higher) that lasts 2 to 3 days
• Headache
• Swollen glands
• Faint red rash (not infectious)
• Tiredness
• Joint pain
• Sore throat
• Cold-like symptoms including a runny nose, cough and puffy eyes

Meningococcal C

• Children may cry and be irritable or generally unhappy
• Fever (i.e. a temperature of 38.5°C or higher)
  
• Soreness, pain and redness at injection site
• A lump at the injection site; this generally disappears after a few weeks and does not need treatment
• Loss of appetite
• Headache (usually in teenagers or adults)

Pneumococcal

• Pain, redness and swelling at the injection site
  
• A lump at the injection site; this generally disappears after a few weeks and does not need treatment
• Fever (i.e. a temperature 38.5°C or higher)

Polio

• Fever (a temperature of 38.5°C or higher)
• Redness, swelling and tenderness at injection site
• A lump at the injection site; this generally disappears after a few weeks and does not need treatment
• Muscle aches

Rabies

• Headache
• Dizziness
• Feeling generally unwell (malaise)
• Muscle pain(myalgia)
• Nausea

Tetanus

• A lump at the injection site; this generally disappears after a few weeks and does not need treatment

Typhoid

Common side effects of the oral typhoid vaccines include:

• Stomach discomfort
• Diarrhoea
• Nausea
• Vomiting
• Rashes

Common side effects of injected vaccines include:

• Feeling generally unwell (malaise)
• Fever (i.e. a temperature 38.5°C or higher)
• Nausea

Whooping cough (pertussis)

• Child may cry more than usual and be irritable
• Drowsiness
• Restlessness
• Painful, red swelling on the arm or thigh that usually disappear without treatment within 2 to 7 days

Yellow fever

• Headache
• Muscle pain (myalgia)
• Nausea
• Diarrhoea
• Weakness

You can learn more about reactions and risks for a number of common vaccines through the Sharing Knowledge About Immunisation website.