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.

An annual influenza vaccination 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 that make people sick can change from year to year, and so 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).

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.

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 one million who gets 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 Guillain-Barré 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.³

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. 

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 had 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.

Information about influenza (flu) disease, vaccines and recommendations for vaccination from the Australian Immunisation Handbook.

National Centre for Immunisation Research and Surveillance: Influenza vaccines for Australians - FAQs