Influenza vaccines – frequently asked questions (FAQs)

Key points

• Influenza is caused by infection with the influenza virus and results in respiratory illness. 
• It is a common cause of hospitalisation and death, particularly in those at greater risk of severe disease. 
• Annual influenza vaccination is recommended for all people aged 6 months and over and is available free under the National Immunisation Program (NIP) for eligible groups at the highest risk of influenza and its complications. 
• All currently available influenza vaccines in Australia are inactivated (non-live) and cannot cause influenza. They are safe for people with immunocompromise and pregnant women. 
• Influenza is seasonal, and yearly vaccination with vaccines tailored to changes in circulating strains each influenza season is required for continuing immunity. 
• Influenza vaccine can be co-administered with (i.e. given on the same day as) most other vaccines.
   

FAQs

What is influenza?

What is the difference between influenza and the common cold?

Who can get influenza, and how common is it?

What are the complications of influenza?

What types of influenza vaccines are available in Australia?

What influenza vaccines are available in Australia?

Who is recommended to receive an influenza vaccine?

Who is eligible to receive a free influenza vaccine under the NIP?

How effective are influenza vaccines in preventing influenza illness?

What is an ‘enhanced’ influenza vaccine, and how is it different from other influenza vaccines?

What are the options for individuals who are not eligible for a free influenza vaccine under the NIP and want to be protected?

How many doses of influenza vaccine are people recommended to receive each influenza season?

For those requiring a second dose, does the same brand of vaccine need to be administered?

When is the optimal time to receive an influenza vaccine?

Should pregnant women receive an influenza vaccine – and if so, when is the optimal to do so?

Does the influenza vaccine create any concerns for breastfeeding mothers, and will it have any impact on milk supply?

Why do healthy infants and young children need an influenza vaccine?

Can the influenza vaccine cause influenza?

What are the common side effects after receiving an influenza vaccine?

Are there any rare side effects that can occur after receiving an influenza vaccine?

Are there any people for whom influenza vaccines may be contraindicated or additional precautions should be taken?

Can a person receive other vaccines at the same time as an influenza vaccine?

Is paracetamol recommended before getting an influenza vaccine, and does it reduce the effectiveness of vaccination?

Should a person receive an influenza vaccine if they have already had influenza?

Why are influenza vaccines funded for certain groups but not others?

How should people protect themselves from influenza if they are travelling overseas or returning to Australia?

Can a person with an egg allergy receive an influenza vaccine?

Can a person with a latex allergy receive an influenza vaccine?

How is the safety of influenza vaccines monitored?
 

What is influenza?

Influenza is an acute respiratory illness that occurs after an infection with an influenza virus. It is often called ‘the flu’. 
Common symptoms include: 

• fever
• dry cough
• nasal congestion
• headache
• sore throat
• general symptoms such as feeling unwell, muscle aches, and pains and fatigue. 

Influenza virus is mainly spread through large droplets from sneezing and coughing; these may be airborne and can be transmitted via inhalation and touching surfaces. 

What is the difference between influenza and the common cold?

A cold may cause some symptoms similar to those caused by influenza, but these symptoms are not caused by influenza viruses. Usually, influenza is more severe and lasts longer than a cold.

Who can get influenza, and how common is it?

Influenza is the most common vaccine preventable disease in Australia – and anyone can get it. 

The number of affected people varies from year to year based on circulating virus strains and the level of immunity in the population. 

In 2023, clinical severity was considered relatively low overall, due to the effectiveness of the 2023 influenza vaccines; however, severe presentations and deaths in children under 16 years were higher compared to previous years. From January to October 2023, 252,296 laboratory-confirmed influenza cases and 376 influenza-associated deaths were notified to the National Notifiable Disease Surveillance System. 

What are the complications of influenza?

A small proportion of people infected with influenza may experience pneumonia, myocarditis and neurological complications. These complications can lead to hospitalisation and death. 

While the highest risk of complications from influenza is in people with pre-existing medical conditions, complications can also occur in healthy individuals.

What types of influenza vaccines are available in Australia?

All influenza vaccines available in Australia are either split virion or subunit vaccines. These vaccines are all inactivated, meaning they do not contain live virus and cannot cause influenza illness. 

Flucelvax Quad is currently the only cell-based inactivated influenza vaccine that has been registered for use in Australia. It is approved for use in people from 6 months of age and funded under the NIP for those in high-risk population groups aged 5–64 years. 

Further information on the different types of influenza vaccines can be found here.

All influenza vaccines available in Australia are quadrivalent, meaning they contain four inactivated influenza virus strains – two influenza A and two influenza B strains.

What influenza vaccines are available in Australia?

Influenza vaccines are available for all people aged 6 months and over; however, different vaccines are registered and available for use in different age groups. 

The Australian Technical Advisory Group on Immunisation Statement on the administration of seasonal influenza vaccines in 2024 includes a table that details all seasonal influenza vaccines registered and available for use in Australia in 2024 (by age) and whether they are funded under the NIP.

Who is recommended to receive an influenza vaccine?

All people aged 6 months and over are recommended to receive an annual influenza vaccine to prevent serious illness and hospitalisation associated with influenza infection. 

Some groups are at a higher risk of influenza-associated complications and are especially recommended to receive an influenza vaccine. For these high-risk individuals, the vaccine is available for free under the NIP. (See the following question.)

Who is eligible to receive a free influenza vaccine under the NIP?

The influenza vaccine is available for free under the NIP for:

• children aged 6 months to 5 years 
• all Aboriginal and Torres Strait Islander people aged 6 months and over 
• all adults aged 65 years and over 
• pregnant women  
• people with certain underlying medical conditions (further detail can be found here).  

States and territories may also provide free influenza vaccination to additional population groups. Check with your state or territory health authority.  

How effective are influenza vaccines in preventing influenza illness?

Extensive research has shown the influenza vaccine is effective.

The effectiveness of the vaccine depends on: 

• the age and health of the person receiving it 
• the match between the vaccine influenza strains and influenza strains circulating in the community.  

In young children and healthy adults aged less than 65 years who have received influenza vaccination, the likelihood of getting influenza is reduced by around 50–60%. This figure varies from year to year.

People with an underlying medical condition and elderly people may not respond as well to the influenza vaccine, so their level of protection from the vaccine may be lower. The vaccine does reduce the risk of influenza-associated pneumonia and hospitalisations. Information about ‘enhanced’ influenza vaccines that are available for older people can be found in the following question.

What is an ‘enhanced’ influenza vaccine, and how is it different from other influenza vaccines? 

An ‘enhanced’ influenza vaccine is specifically designed to increase the response of the immune system to the vaccine. It can contain: 

• the standard amount of antigen but with an adjuvant (a compound that stimulates a higher immune response to a vaccine) added 
• a higher amount of antigen but with no adjuvant added. 

Elderly people do not respond as well to standard-dose influenza vaccines as younger adults, and the level of protection they get from influenza vaccine is usually less than that of a younger person. Enhanced influenza vaccines for people aged 65 years and over offer better protection from influenza infection. 

Two enhanced influenza vaccines are available in Australia for older people in 2024:

• Fluad Quad (adjuvanted), which is registered for people aged 65 years and over
• Fluzone High-Dose Quadrivalent, which is registered for people aged 60 years and over.

While both of these enhanced vaccines are recommended over standard-dose influenza vaccines for people aged 65 years and over, only Fluad Quad is available free under the NIP in 2024.

What are the options for individuals who are not eligible for a free influenza vaccine under the NIP and want to be protected?

People who are not eligible for an NIP-funded influenza vaccine can purchase an influenza vaccine through an immunisation provider (e.g. pharmacists, general practitioners).

How many doses of influenza vaccine are people recommended to receive each influenza season?

Most people only require 1 dose of influenza vaccine each year for full protection.

Certain population groups are recommended to receive a second dose of influenza vaccine during the influenza season, however. These include:  

• children aged 6 months to less than 9 years receiving their influenza vaccine for the first time; 2 doses 4 weeks apart are required for an adequate immune response. (Children who received 1 or more doses of influenza vaccine in a previous season only need 1 dose in the current season and future seasons)
• people who have had a haematopoietic stem cell transplant or solid organ transplant and are receiving influenza vaccine for the first time after the transplant.

Optimal protection offered by the influenza vaccine lasts for 3–4 months following vaccination; after this, the level of protection begins to decrease. 

Receiving a single dose of the influenza vaccine when it becomes available each season is the best measure to protect against severe influenza illness. 

There is currently not enough evidence to support a recommendation for the general population to receive a routine second dose of influenza vaccine during a single influenza season, even where an influenza vaccine was given early in the season.

For those requiring a second dose, does the same brand of vaccine need to be administered?

Two different vaccine brands may be administered when 2 doses of influenza vaccine are required, provided the vaccines are licensed for the relevant age group.

When is the optimal time to receive an influenza vaccine?

The influenza vaccine is recommended before the start of the influenza season – which is typically around May in Australia. Optimal protection lasts for 3–4 months following vaccination. 

Immunisation providers should start administering influenza vaccinations as soon as the vaccine is available. 

The timing of the peak of influenza activity in Australia can vary each year. It typically occurs between May and September, but infections can occur year-round; the vaccines are therefore also available outside of the influenza season. 

It is never too late in the influenza season to get an influenza vaccine. 

Should pregnant women receive an influenza vaccine – and if so, when is the optimal to do so?

Influenza vaccine is recommended in every pregnancy, and it is safe for pregnant women to receive the vaccine at any stage of pregnancy. 

Women who are in their first trimester during the first quarter of the year may consider waiting until the seasonal influenza vaccine for the current year becomes available rather than receiving the influenza vaccine from the previous year. 

Pregnant women who received an influenza vaccine anytime in 2023 should revaccinate if the 2024 influenza vaccine becomes available before the end of pregnancy. 

Women who received an influenza vaccine before becoming pregnant should be revaccinated during pregnancy to protect the unborn infant.

During pregnancy, maternal antibodies produced from vaccination are transferred from the mother to the baby through the placenta. Maternal vaccination reduces the risk of influenza by around 50% in infants under 6 months who are too young to be vaccinated themselves.

Influenza vaccine can be given safely at the same time as the pertussis (whooping cough) vaccine, which is also recommended and NIP-funded during pregnancy.

Does the influenza vaccine create any concerns for breastfeeding mothers, and will it have any impact on milk supply?

Influenza vaccination is safe for breastfeeding women and can provide protection to the baby through antibodies that are transferred to the baby through breastmilk. 

Decreased milk supply has not been associated with receipt of the influenza vaccine; however, being sick due to infection with influenza virus can have a negative impact on milk supply.

Why do healthy infants and young children need an influenza vaccine?

Influenza vaccination is recommended and funded under the NIP for all children aged 6 months to less than 5 years. Children in this age group – including those without pre-existing medical conditions – are more likely to get severe influenza infection resulting in hospitalisation.  

In 2017, approximately 1 in 400 children were diagnosed with laboratory-confirmed influenza. Previously healthy children infected with influenza can become severely ill and suffer from influenza-associated complications such as pneumonia and encephalitis.

Can the influenza vaccine cause influenza?

Influenza vaccines cannot give a person influenza, because they do not contain a live virus. 

The immune response of the body after vaccination may result in side effects that are similar to early influenza symptoms – however, these generally only last for 1–2 days and are much milder than the symptoms of actual influenza. 

Sometimes people are infected with influenza just before they have received the vaccine or after they have received it but before it has had time to work (up to 2 weeks). This can lead to the mistaken view that the influenza vaccine has caused the infection. Other viruses can also be mistaken for influenza.

What are the common side effects after receiving an influenza vaccine?

Between 1% and 10% of people who have an influenza vaccine experience a fever, headache, general tiredness or muscle aches. These symptoms can last for 1–2 days. 

Approximately 10% of people who have an influenza vaccine experience swelling, redness or pain at the injection site. 

Further information can be found in the Australian Government Department of Health and Aged Care resource Following vaccination – what to expect and what to do.

Are there any rare side effects that can occur after receiving an influenza vaccine?

In rare circumstances, infants and children who receive an influenza vaccine may experience a type of seizure known as a febrile convulsion. This can happen when an infant’s or child’s temperature goes up suddenly (fever). However, influenza infection itself can also cause fever – and results in many more febrile seizures than vaccination. 

Enhanced safety monitoring systems for influenza vaccines, such as AusVaxSafety, have confirmed that influenza vaccination is safe in children under 5 years; low rates of fever and medical attendance after vaccination have been reported. 

More serious side effects following influenza vaccination are very rare. Anaphylaxis occurs in approximately 1 in 1 million people who receive an influenza vaccine. Guillain-Barré syndrome (GBS) occurs at a very low rate of less than 1 in 1 million doses of influenza vaccine. Studies have also shown that a person is more likely to get GBS from infection with the influenza virus than from an influenza vaccine.

Are there any people for whom influenza vaccines may be contraindicated or additional precautions should be taken?

There are few contraindications and precautions to receiving influenza vaccines. 

The only absolute contraindication to influenza vaccines is diagnosed anaphylaxis to a previous dose of any influenza vaccine or anaphylaxis after receipt of any component of an influenza vaccine. 

People who have experienced severe reactions after receiving a previous influenza vaccine should consult with their immunisation provider. 

Certain rare medical conditions may lead to an increased risk of side effects from influenza vaccines. Individuals with these conditions should consult with their provider prior to receiving an influenza vaccine. This includes the following patients:

• Individuals with a history of Guillain-Barré syndrome (GBS) where the first episode occurred within 6 weeks of influenza vaccination. The potential for recurrence of GBS if vaccinated, the potential for exacerbation of GBS following influenza infection and alternative protective strategies (e.g. vaccination of household members) should be discussed. Vaccination can be considered in special circumstances.
• People who are taking immune checkpoint inhibitors. Immune checkpoint inhibitors are a class of monoclonal antibodies currently used in the treatment of several cancers. Individuals who are taking more than one checkpoint inhibitor may have a higher risk of immune-related adverse events following immunisation with influenza vaccine. The person’s treating oncologist should be consulted about the risks and benefits of influenza vaccination.

Can a person receive other vaccines at the same time as an influenza vaccine?

Yes. People, including infants and children aged 6 months and over, can receive an influenza vaccine at the same time as most other vaccines. If only two vaccines are co-administered, it is recommended to give one vaccine into each limb. If two vaccines need to be administered in the same muscle, there should be a distance of 2.5 cm between injections.

Is paracetamol recommended before getting an influenza vaccine, and does it reduce the effectiveness of vaccination?

Taking paracetamol prior to influenza vaccination is not routinely recommended. However, there are no current data that suggest the effectiveness of the influenza vaccine will be impacted if paracetamol is administered before influenza vaccination.

Should a person receive an influenza vaccine if they have already had influenza?

Yes, influenza vaccination is still recommended following a recent influenza infection. Vaccination can lower the risk of becoming ill from other strains of the influenza virus. 

People who have had influenza in a previous season are recommended to be vaccinated for each new influenza season. This is because strains of influenza change each year and new-season influenza vaccines are reformulated to match circulating strains as closely as possible.

Why are influenza vaccines funded for certain groups but not others?

The Australian Government Department of Health and Aged Care decides which vaccines to fund under the NIP and for which population groups. 

The Pharmaceutical Benefits Advisory Committee provides advice and recommendations to the Department of Health and Aged Care to inform these decisions.

For further information, see National Immunisation Program (NIP) vaccine listing process.

How should people protect themselves from influenza if they are travelling overseas or returning to Australia?

Influenza vaccination is recommended prior to overseas travel, especially if it is known that influenza is circulating in the destination region.

A northern hemisphere formulation of influenza vaccine may be preferred prior to travel to the northern hemisphere during its influenza season, but this is generally unavailable in Australia. The southern hemisphere formulation is considered an acceptable alternative. 

Individuals who have received a current southern hemisphere influenza vaccine earlier in the influenza season and are travelling to the northern hemisphere during its influenza season (usually, from October to May) may receive a second dose of influenza vaccine prior to travel (ideally, 2 weeks before departure).

For people who have recently returned to Australia from living or travelling overseas, influenza vaccination with the currently available local vaccine is recommended, regardless of the time of the year.

Further information about influenza vaccination for travellers is available in the Australian Immunisation Handbook. 

Can a person with an egg allergy receive an influenza vaccine?

People with an egg allergy can be safely vaccinated with any influenza vaccine (including egg-based vaccines – which usually contain less than 1 μg [microgram] of egg protein per dose – and the cell-based vaccine). 

Reactions such as hives, skin reactions or anaphylaxis (severe allergic reaction) are rare side effects following influenza vaccination, regardless of known egg allergy. 

Australasian Society of Clinical Immunology and Allergy (ASCIA) guidelines offer additional information on influenza vaccination of individuals with an allergy to eggs, including regarding risk, dosage and observation period.

Can a person with a latex allergy receive an influenza vaccine?

Influenza vaccines used in Australia are latex-free and are safe for use by people with a latex allergy or sensitivity. 

While the product information for Fluarix Tetra states that some presentations of the vaccine cannot be considered latex-free, presentations that may contain latex are not supplied in Australia. 

How is the safety of influenza vaccines monitored?

The Therapeutic Goods Administration (TGA) assesses the quality of every batch of vaccine, including influenza vaccine, before it is distributed in Australia. It also collects, analyses and reports data on vaccine side effects once a vaccine is in use. 

Individuals and healthcare providers can also report side effects directly to the TGA. 

Additionally, programs such as AusVaxSafety collect information from individuals regarding side effects experienced after vaccination, including influenza vaccination. Experts analyse this information to detect any safety problems as soon as possible.

Useful links

• 2024 influenza vaccination – program advice for vaccination providers – Australian Government Department of Health and Aged Care
• 2024 influenza (flu) vaccination – consumer fact sheet – Australian Government Department of Health and Aged Care
• Approach to influenza vaccination in patients with a history of Guillain–Barré Syndrome [PDF] – AusVaxSafety
• ATAGI statement on the administration of seasonal influenza vaccines in 2024 – ATAGI
• Influenza chapter – Australian Immunisation Handbook
• Influenza vaccine coverage data – NCIRS
• Influenza vaccines – AusVaxSafety
• National Immunisation Program Schedule – Australian Government Department of Health and Aged Care 
• Vaccination of the egg-allergic individual – ASCIA