Common questions

Why does my child need a flu shot?

Flu shots, called influenza vaccines, are recommended for babies and children every year from the time they are six months old to protect them from influenza. Influenza vaccines are free for all children aged six months to under five years.

Isn’t the flu just a bad cold?

Influenza (sometimes called ‘the flu’) can be much worse than a bad cold. Some babies and children who have influenza get so sick they can’t go to childcare or preschool for two weeks or more. Every year in Australia, hundreds of children get so unwell from influenza they need to be treated in hospital. Most of them are babies and children under five years.

Do influenza vaccines actually work?

An influenza vaccine is the best way to protect your child from serious influenza. Influenza vaccines give better protection in some years than others. This is because the types of influenza viruses making people sick from year to year can change, and the vaccines may have to be updated. 

Before the influenza season, experts gather information from around the world to work out which influenza viruses are most likely to circulate. They often get it right, but sometimes it can be hard to predict. Experts use the best information available at the time.

Influenza vaccines give your child good protection, even if they aren’t always perfect. By getting an influenza vaccine, your child will be less likely to get influenza, and less likely to get the serious conditions that influenza can cause, like severe lung infections (pneumonia) or swelling in the brain (encephalitis).

Could my child get influenza from the vaccine?

Your child can’t get influenza from an influenza vaccine. Influenza vaccines contain pieces of influenza viruses, but these can’t make your child sick like the whole virus. Some vaccines given to children in other countries have whole, weakened influenza viruses in them, but these vaccines are not used in Australia. 

It’s normal for babies and children to be a bit unsettled or even feverish for a day or two after influenza vaccination. While these side-effects can look like the flu, they are a sign that your child’s immune system is responding to the vaccine, which is exactly what’s supposed to happen. Also, the vaccine starts to protect your child after about two weeks, so if your child caught the virus before they were vaccinated (but wasn’t feeling sick yet), or in the two weeks after they were vaccinated, it might seem like the vaccine made them sick.

I’ve heard influenza vaccines can have serious side effects. Is this true?

Serious side effects are very rare. Less than two in every 100,000 children under two years have febrile convulsions (fever fits or seizures) in the days after vaccination.1 Febrile convulsions are caused by a sudden increase in body temperature. They can be frightening, but are usually harmless. Children are much more likely to have febrile convulsions if they get sick from influenza. In one study, about four in 100 children who were treated in hospital for influenza had a febrile convulsion.2

About one child out of every million who get an influenza vaccine has a severe allergic reaction (anaphylaxis) to one of the ingredients. Any reactions usually occur before you leave the clinic, and the medical staff are trained to help children who have this reaction recover quickly. Anaphylaxis is frightening but extremely rare.

It’s safe for children with egg allergies to get influenza vaccines.3 This is because the amount of egg in influenza vaccines is tiny (usually less than 1 microgram of egg protein per dose, which is too small to trigger an allergic reaction). Many years ago, influenza vaccines used to contain more egg protein, but the way the vaccines are manufactured is much better now. 

About one in one million (1,000,000) people who get an influenza vaccine get Guillian-Barre syndrome, which is a disorder that can cause muscle weakness, numbness and paralysis. Although it can be very serious, most people who get this disorder don’t experience any long-term effects. People infected with influenza are more likely to get Guillain–Barré syndrome than people who get the influenza vaccine.14

Does my child really need an influenza vaccine every year?

Children and babies six months or older need to get an influenza vaccine every year. This is because the types of influenza viruses circulating often change from year to year. Also, protection from an influenza vaccine generally lasts less than a year.

The best time to get an influenza vaccine is in April or May, before the influenza season, which is usually June to September. Your child can get an influenza vaccine at the same time as other vaccines.

How can we be sure influenza vaccines are safe?

Influenza vaccines must be assessed for safety by the Therapeutic Goods Administration (TGA) before they can be used in Australia. 

Once the TGA approves an influenza vaccine, it doesn’t need to be tested each year. Although the types of influenza virus particles in the vaccines may change from year to year, the way the vaccines are manufactured stays much the same. Influenza vaccines only need to be tested for safety again if the manufacturing process changes.

There are systems in place to detect any unexpected side-effects while a vaccine is being used.  For example, AusVaxSafety collects information about side-effects directly from people who have gotten the vaccine, and publishes this information every week during influenza season. The TGA, along with other health authorities and experts, investigate any potential issues detected through these monitoring systems. In very rare circumstances, they may suspend use of a vaccine. 

This is what happened in 2010, when one brand of influenza vaccine (Seqirus/ bioCSL Fluvax and Fluvax Junior) was found to have caused febrile convulsions in children under five years. We don’t give this specific vaccine to babies or children in Australia anymore.

Why is the schedule the way it is?

The schedule is carefully planned to protect babies and children as soon as it is possible.

Some vaccines don’t work if babies get them too young, so we give those vaccines to babies when they’re older. The measles vaccination is one of these.

Some diseases are much more serious when very young babies get them, so we recommend vaccinating against them when babies are very young. Pertussis (also known as whooping cough) is one of these.

It takes many years of careful research by independent experts to work out the right time to give each vaccine so that they get the best possible protection against serious infectious diseases as soon as they can.

Why do children get so many vaccines in the first two years?

Children get as many vaccines as possible in the first two years so they can be protected as soon as possible from diseases that can be serious.

It takes many years of research to work out the right time to give each vaccine. Independent experts gather information to help them make their recommendations. They consider which diseases Australian children are most likely to be exposed to; how serious those diseases can be for children at different ages: which vaccines are safest and which work best; how many doses are needed to provide full protection; and the age when the vaccines will give the best protection.

What happens if I delay or leave out certain vaccines?

When vaccination is delayed or spaced out, children are left without protection from diseases for longer than they need to be. That’s why we recommend vaccinating children on time – so they can be protected as soon as possible.

Children and babies are often more likely to catch infectious diseases when they are young, and more likely to get seriously ill when they do catch them. The National Immunisation Program Schedule has been designed to protect children when they need it most.

If you choose to space out the vaccines, it means your child will need to have more vaccination appointments. Researchers have found that visiting the doctor for one needle is just as stressful for children as visiting the doctor for two needles at once.1

Are the diseases still around anyway?

Some of the diseases children are vaccinated against, like whooping cough and flu, are still common among children living in Australia. In 2017 four people caught tetanus. One was a boy under four years old and one was a girl between 5 and 9 years old (10).

Others, like measles are less common in Australia but are more common in nearby countries in the Pacific and South East Asia. Vaccinating your child will protect them from diseases which could be brought into Australia by travellers, or which they might catch if they travel overseas with you.

Some of the diseases we vaccinate children against, like polio, have become very rare in Australia because vaccination has stopped them from spreading. We still vaccinate Australian children against these diseases to stop them from coming back.

Why has the schedule changed since I had my last baby?

The schedule of recommended vaccinations changes from time to time for a number of reasons. For example:

  • A new vaccine could be added to the schedule, protecting children from a disease it hasn’t been possible to protect them from before.

  • A ‘combination vaccine’ that provides protection against multiple diseases might be released after years of research and development, reducing the number of needles children need to get overall.

  • A vaccine that is better, safer, more effective or less expensive than previous versions might be introduced.

Sometimes booster doses are added to the schedule to strengthen the protective effect of a vaccine.

Why is the schedule different in other countries?

The schedule is different in other countries because patterns of disease, strains of viruses or bacteria, medical care, available vaccines and their costs vary from country to country.

Medical experts and health economists consider all the available information about children and diseases and decide which vaccines should be given to children in their countries at what ages. In Australia, medical experts and health economists from a variety of independent advisory groups decide which vaccines should be provided to children living in Australia.2

What is in the vaccines?

The most important part of a vaccine is the antigen. Other ingredients include adjuvants, preservatives, stabilisers, and diluents. Some of these are added to protect and support the antigen. Tiny traces of substances used in the process of producing antigens can also be detected in vaccines (residues). All ingredients in vaccines are tested for safety.

What are antigens?

Antigens train the immune system to clear disease-causing germs (bacteria or viruses) from the body quickly, before they can cause serious illness.

Most antigens are fragments of germs. Some antigens are weakened or killed germs or substances made by germs, called toxins.

Combination vaccines, given in a single needle, contain more than one antigen, which reduces the number of needles children need to be fully protected.

What are adjuvants?

Adjuvants help strengthen the immune system’s response to the antigens in vaccines. In some cases this means fewer needles are needed for a child to be fully protected against a disease.

The most commonly used adjuvants are salts called aluminium hydroxide, aluminium sulphate and potassium aluminium sulphate. They are commonly referred to as ‘alum’. The amount of aluminium contained in vaccines is tiny.

What are preservatives?

Preservatives protect vaccines from becoming contaminated with harmful bacteria or fungi. The most common preservative used in vaccines is a tiny amount of alcohol.

Thiomersal, which is a salt that contains a tiny amount of mercury, is no longer used as a preservative in any vaccines routinely given to children in Australia. This is because the vaccines we use come in a single dose package and therefore do not need a preservative. Thiomersal is still used in some other parts of the world where single dose packages are too expensive or too expensive to transport. However, it is safe and effective as a preservative.

What are stabilisers?

Stabilisers are usually sugars or oils that prevent vaccines from going off (spoiling) or sticking to the sides of their containers or syringes.

What are residues?

Residues are tiny amounts of substances that remain in the vaccine after the manufacturing process.

Most of these substances are removed from the final vaccine product, but small amounts remain. In such tiny amounts, these residues are harmless, and most are already present in our bodies. For example, tiny traces of formaldehyde can be detected in some vaccines. Formaldehyde is used to inactivate viruses, so they can be safely used as antigens in vaccines. Much larger amounts of formaldehyde are produced naturally in healthy human bodies than can be detected in vaccines.3

What are diluents?

The diluent used in vaccines is usually sterile water or saline (salt water). Diluents have no effect on the body. They are included in vaccines to ensure that the smallest useful dose can be given to children. Vaccines are mostly made up of water or saline.

How do I know the vaccines are safe?

All vaccines go through lengthy and rigorous testing processes and must pass through three phases of clinical trials to ensure they are safe before they are approved for use in Australia.

How are vaccines tested?

Safety research and testing is an essential part of developing vaccines. Vaccines are first tested on animals. Then, if a vaccine is found to be safe in animal trials, it is evaluated in humans in three phases of clinical trials:

  • Phase 1 trials: The new vaccine is given to a small number of healthy adults (25-50) with the primary aim of assessing safety.

  • Phase 2 trials: If the new vaccine is found to be safe in Phase 1, it is then given to hundreds of people to determine how effectively it stimulates immune responses; how much or how many doses need to be given in order to protect against the target disease; and whether there are any side effects.

  • Phase 3 trials: If the vaccine is found to be effective and safe, it is then given to many thousands of people to test whether it protects large populations from the target disease and check if there are any uncommon or serious side effects. Every vaccine given to Australian children must pass all of those phases before it is registered for use by the Therapeutic Goods Administration (TGA).

Could there be side effects we don’t know about?

Some side effects are so rare they can’t be detected even after studying the effects of a vaccine on tens of thousands of people. For that reason, the safety of vaccines continues to be monitored even after they are in routine use. Reports of possible side effects made by parents and health professionals are carefully reviewed. These reviews can signal the need for further investigation and studies.

In addition, large populations of people who receive vaccines are often studied to identify any possible links between vaccination and rare or serious health conditions.

What happens if a problem is suspected?

Any suspected problem with a vaccine is thoroughly investigated by the Therapeutic Goods Administration (TGA). These investigations involve other health authorities including state and federal governments and medical experts. Investigations usually involve more tests of vaccine quality and manufacturing processes and studies of vaccinated and unvaccinated people who have and who have not had reactions.  

If a suspected problem could be serious, authorities will consider a range of actions including suspending use of the vaccine during the investigation.

This is what happened in 2010 when doctors and parents began reporting that some children were experiencing febrile seizures (fever fits) after receiving an influenza vaccine. Febrile seizures are caused by a sudden increase in body temperature and are usually harmless.4 I Influenza vaccination for children was temporarily suspended until the matter could be investigated.

The investigation found that children who received one particular brand of influenza vaccine – BioCSL FluvaxTM – experienced febrile seizures much more often than children who received other brands. That vaccine is no longer registered for use in children under five years of age but there are other seasonal influenza vaccines that children can have.

How do vaccines affect immunity?

Vaccines train your baby’s immune system to quickly recognise and clear out germs (bacteria and viruses) than can cause serious illness. Vaccines will strengthen your baby’s immune system a bit like exercise strengthens muscles.

Can vaccines overwhelm a baby’s immune system?

Vaccines can’t overwhelm a baby’s immune system because their immune system is equipped to protect them from thousands of germs every day. From the moment they are born, babies are exposed to countless germs (bacteria and viruses) through their skin, noses, throats and guts. Babies’ immune systems are designed to deal with this constant exposure to new things, learning to recognise and respond to things that are harmful.  

Vaccination does not interfere with the ability of your baby’s immune system to respond to other germs. Even if all the doses on the immunisation schedule were given to a baby at the same time, only a small fraction of available immune cells would be occupied.

Would it be safer to vaccinate babies when they’re older?

Vaccinating babies when they are older leaves them without protection against diseases that can be serious. This means they aren’t protected at an age when those diseases are most common or most serious.

Babies and young children are most vulnerable to infections when they are very young. Vaccinating them before they come into contact with serious infectious diseases gives babies the best possible protection.

Would it be better for children to develop their own immunity?

Allowing children to develop immunity by catching infectious diseases is not safe. Catching a vaccine-preventable disease can protect a child from catching it again, but it can also make them seriously ill in the process. Occasionally children in Australia still die as a result of catching a vaccine-preventable disease.

Vaccination is recommended because it is the safest way to develop immunity. Vaccines are designed to stimulate immunity without causing disease. The side effects of vaccination are usually mild (like getting a sore arm) and pass quickly but the diseases they prevent can cause serious illness requiring hospital treatment.

Are the diseases still around anyway?

Some of the diseases children are vaccinated against, like whooping cough and flu, are still common among children living in Australia. In 2017 four people caught tetanus. One was a boy under four years old and one was a girl between 5 and 9 years old 10.

Others, like measles are less common in Australia but are more common in nearby countries in the Pacific and South East Asia. Vaccinating your child will protect them from diseases which could be brought into Australia by travellers, or which they might catch if they travel overseas with you.

Some of the diseases we vaccinate children against, like polio, have become very rare in Australia because vaccination has stopped them from spreading. We still vaccinate Australian children against these diseases to stop them from coming back.

What about autism?

Many large studies have found that vaccines do not cause autism. The idea that vaccination caused autism was attractive to some people who wanted to find a clear cause. However, this idea arose from a few studies that were badly conducted and have since been proven wrong. Current research suggests that autism cannot be explained by a single cause, but is probably due to a combination of developmental, genetic and environmental factors.

How do we know that vaccines do not cause autism?

A number of high-quality studies have compared the health of large numbers of vaccinated and unvaccinated children over many years. The largest study included 537,303 children born in Denmark and found that unvaccinated children were just as likely to develop autism as vaccinated children.5 When the results of this study were combined with the results of nine other studies to include medical information from nearly 1.5 million children living all around the world, researchers were able to confirm that vaccination could not be causing autism.6

Why do some people believe there is a connection?

Some people think there is a connection because a British a research group, led by Andrew Wakefield, suggested that some children who had received the measles-mumps-rubella (MMR) vaccine went on to develop bowel disease and developmental disorders such as autism.7 The results of the research, which had included only twelve children, were published in a respected medical journal in 1998. However, in 2004 the authors retracted their claim that there was any association between vaccination and autism. The paper was withdrawn from the journal in 2010 after the General Medical Council found that results reported in the paper had “proven to be false”.8 The journal printed an apology.9

After it became clear that the MMR vaccine was not the problem, some people suggested a preservative sometimes used in vaccines packaged in multi-dose containers might be linked to autism. The preservative, called thiomersal, is a salt that contains a tiny amount of mercury. The mercury salt in thiomersal (ethylmercury) is not like the mercury compound (methylmercury) that accumulates in the human body.

None of the vaccines normally given to children in Australia are packaged in multi-dose containers, so none of them contain thiomersal or any other form or mercury.

Can I get my child separate vaccines for measles, mumps, rubella vaccines?

You can’t get separate vaccines for measles, mumps, and rubella for your child because they are not available in Australia. Some people suggest using separate vaccines for measles, mumps, and rubella instead of the combined measles, mumps, and rubella (MMR) vaccine. Medical researchers are confident that vaccines don’t cause autism.

  1. Ramsay, DS and Lewis, M. Developmental change in infant cortisol and behavioural response to inoculation. Child Development 1994;65:1941-1502
  2. Nolan, T. The Australian model of immunization advice and vaccine funding. Vaccine 2010; 28 Suppl 1:A76-83 
  5. Madsen, KM. et al. A population-based study of measles, mumps, and rubella vaccination and autism. New England Journal of Medicine 2002;347: 1477-1482 
  6. Taylor, LE. et al. Vaccines are not associated with autism; an evidenced-based meta-analysis of case- control and cohort studies. Vaccine 2014;32:3623-3629 
  7. Wakefield, AJ et al. RETRACTED: Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet 1998.351:637-641
  8. Deer, BN. How the case against the MMR vaccine was fixed. BMJ 2011;342-c5347
  9. Retraction – Ileal-lymphoid-nodular hyperplasia, non-specific colitis and pervasive developmental disorder in children. Lancet 2010:375:445
  10.  National Notifiable Disease Notification Surveillance System
  12. Hambidge, S.J., et al., Safety of Trivalent Inactivated Influenza Vaccine in Children 6 to 23 Months Old. JAMA, 2006. 296(16): p. 1990-1997. Available at:
  13. Dawood, F.S., et al., Complications and associated bacterial coinfections among children hospitalized with seasonal or pandemic influenza, United States, 2003-2010.(Report). Journal of Infectious Diseases, 2014. 209(5): p. 686. Available at:
  14. National Centre for Immunisation Research and Surveillance. Influenza vaccines - Frequently Asked Questions (NCIRS Fact sheet). NCIRS: Sydney, Australia. Available at: 

Other information for parents who have questions