Influenza vaccines and COVID-19

This year, with all the focus on the COVID-19 vaccine rollout, it’s easy to forget about another important vaccine – your annual flu jab. Regardless of the season, it is important to take action to be protected against both of these potentially severe infections.

Influenza vaccines and COVID-19

What do we know about the 2021 flu season?

A person can be infected with influenza (flu) at any time of the year. But in Australia flu infections tend to be more common between June and September. This is what is referred to as the ‘flu season’.

In 2021, fewer Australians were diagnosed with influenza than in previous years.1,2 Physical distancing and hygiene measures put in place to slow COVID-19 transmission likely also slowed the spread of other infectious diseases, including influenza.3 As international borders gradually reopen and people start moving about, including those who have recently returned from overseas, the rate of influenza transmission is expected to increase. This may potentially occur outside of the usual flu season.

‘Although the current rate of influenza infections appears low, the flu can still cause serious illness, particularly among those at high risk such as the elderly,’ says Dr Anna Samecki, medical adviser at NPS MedicineWise.

The same is true for COVID-19 infections in the Australian community. Public health advice about maintaining physical distance, wearing masks and practicing good hygiene have helped keep community levels of transmission low. But outbreaks have occurred and will continue to do so as long as the SARS-CoV-2 virus (that causes COVID-19 infections) is around. 

As with influenza vaccinations, having a COVID-19 vaccination provides an extra level of protection against being infected and also helps slow the spread of infection to others who may be more vulnerable to severe complications.


Do I need a flu vaccine this year?

The flu is caused by influenza viruses of types A, B, C or D.4 Most flu-related illnesses are caused by influenza type A or B viruses. Influenza viruses are constantly changing parts of their genetic code (through mutations). 

Over time a virus may become different enough that it is no longer recognised by a person’s immune system. This increases the chance of infection and of this variant being passed on to other people to become the dominant strain causing illness.

Constant mutation means that the dominant strain one year may not remain the dominant strain in following years.5 This is why the influenza vaccines change each year – to better match the likely strains causing infection. It is also why people are advised to have a flu jab every year – so they can produce the antibodies best matched to defend against the influenza viruses currently in circulation.

Whether you have had flu previously or have had an influenza vaccination in the past, current evidence suggests that any antibodies you made will become less protective with time.5 This may be because the level of antibodies in your body declines, or because the antibodies you have do not work against the influenza types currently causing infection.

In Australia, the influenza vaccine rollout is guided by advice from the World Health Organisation (WHO). It recommends which influenza strains should be included in the next season’s vaccines, based on analysis of recent flu seasons.5

These recommendations are made in September for countries in the southern hemisphere. The Australian Influenza Vaccine Committee meets with the Therapeutic Goods Administration to consider the WHO recommendations and confirms the strains to be included in Australian flu vaccines.6

This year, eight quadrivalent influenza vaccines have been approved for use in Australia.7,8 Quadrivalent flu vaccines protect against four of the most common influenza strains currently causing infections.

A note about effectiveness

The level of protection provided by a flu vaccine can vary according to a person’s age, any health conditions they have, how much flu virus is circulating in the community and how good a match the vaccine is for the virus strains that are the most prominent for that season.4

That said, influenza vaccinations are a major strategy in reducing the number of people who are infected with influenza during the year and clinical findings suggest if someone does become infected, the severity of an infection will likely be much reduced after immunisation.8


Does age matter with flu vaccines?

Although there are multiple influenza vaccines available, they are not all for general use.

Each year ATAGI makes recommendations on the influenza vaccines that are appropriate for each age group. These recommendations are informed by clinical trials, information gathered once the vaccines are in use, and data collected from WHO.

‘Certain age groups are particularly vulnerable to the flu and have higher rates of complications and hospitalisations’, says Dr Samecki. ‘That is why some flu vaccines have age restrictions, as they are designed to boost the immune response in those most vulnerable. A good example is FluadQuad, which is specifically for adults aged over 65 years.’

The Australian Government has set aside millions of influenza vaccine doses as part of the National Immunisation Program (NIP). The NIP provides these doses for free to people in our community who are most at risk from complications if they are infected with influenza.

Age group

Influenza vaccine funded under NIP

Children between the ages of 6 months and 5 years

Vaxigrip Tetra

Fluarix Tetra

People between the ages of 6 months and 65 years who have specific medical conditions

Vaxigrip Tetra

Fluarix Tetra

Afluria Quad

Aboriginal and Torres Strait Islander people aged between 5 years and 65 years

Vaxigrip Tetra

Fluarix Tetra

Afluria Quad

People who are pregnant

Vaxigrip Tetra

Fluarix Tetra

Afluria Quad

People aged 65 years and over

Fluad Quad

People who are not eligible for a flu jab through the NIP can arrange to receive their vaccination through their GP or another recognised immunisation provider. In all cases there may be costs involved if a consultation is needed. It is wise to check about costs before going to have your vaccination, even if you think you are eligible under the NIP.

A summary statement about the influenza vaccines available for use in Australia in 2021 – Updated December 2021 is available from ATAGI.

If you have any questions about which flu vaccine is best for you, speak to your trusted health professional or call the National Immunisation Information Line on 1800 671 811 for general advice and information about immunisation, Monday to Friday from 8:30 am to 5 pm Australian Eastern Standard Time.

You can also use the NPS MedicineWise Medicine Finder to read, download or print the Consumer Information Leaflet for each of these vaccines.


Will COVID-19 vaccinations be seasonal like the flu vaccine?

COVID-19 has been around for almost 2 years. A lot of research has been conducted on the SARS-CoV-2 virus in that time, including the development of almost 300 different vaccines (some at laboratory phase, other in trial phases).9 We have also seen a number of variants emerge as the SARS-CoV-2 virus undergoes natural changes to its genetic code (mutations).10

Clinical trials are underway to understand how effective the currently available COVID-19 vaccines are against variant strains of the SARS-CoV-2 virus. Some early or preliminary reports suggest that the vaccines can still protect against infections caused by variant strains but not as well as they do against the original SARS-CoV-2 virus.11-15 Some companies are already working on new vaccines that better target variants, so it is possible that booster or seasonal COVID-19 vaccines may be recommended in the future if variant strains continue to emerge.

It is still unclear how long immunity lasts after COVID-19 vaccination. Natural immunity may be short-lived, with reinfection of COVID-19 likely to occur within 3 months.16 Ongoing studies for the mRNA vaccines by Pfizer/BioNTech and Moderna have reported immunity from the virus lasting 6 months after a second dose.17,18

In Australia, four of the most extensively tested and studied vaccines have provisional approval for use: Comirnaty (Pfizer/BioNTech); Vaxzevria (AstraZeneca; previously COVID-19 Vaccine AstraZeneca; ChAdOx1-S); COVID-19 vaccine Janssen (Janssen-Cilag); and Spikevax (Moderna). At the moment the expert clinical recommendation is that each eligible person has two doses of the same vaccine to provide maximum immunity. Needing multiple doses is common for many other vaccines that people may also receive during their lifetimes.


If I get the COVID-19 vaccine, do I still need a flu jab?

Yes. A flu vaccine will not protect you against COVID-19. A COVID-19 vaccine will not protect you from being infected with the flu.

Influenza and COVID-19 are both viral infections that affect the respiratory (breathing) system. But they are caused by different viruses. COVID-19 is caused by the coronavirus SARS-CoV-2. Influenza is caused by influenza viruses.

The vaccines being developed against COVID-19 are specific to the SARS-CoV-2 virus. These vaccines trigger your immune system to make antibodies that are specific to the SARS-CoV-2 virus. These antibodies cannot work against any other type of virus.

Flu vaccines are developed to target the types of influenza viruses that are likely to be most common in the approaching flu season. A flu vaccine can trigger your body to create antibodies to fight influenza viruses. It will not help trigger an immune response to SARS-CoV-2.

COVID-19 and the flu are both highly contagious diseases. The best way to prevent the spread of either infection is to get vaccinated. You should also continue to practice good hygiene (washing hands regularly, coughing and sneezing into a tissue or your elbow etc) and physical distancing to protect yourself and others – especially those who are unable to be vaccinated against one or both of these diseases.


Can I get both vaccines at the same time?

The Australian Technical Advisory Group on Immunisation (ATAGI) and the Commonwealth Department of Health have advised that a flu vaccine can be given at any time before or after, or with a COVID-19 vaccine. This allows your immune system time to fully respond to each vaccine. In the unlikely scenario that you have a reaction to one of the vaccines, it also makes follow-up and side effect reporting a lot easier.

An ideal time to get the flu vaccine, if available, could be at the same time as the COVID-19 booster vaccine.

Use the COVID-19 Vaccine Eligibility Checker to find out when you are able to plan your COVID-19 vaccine.

The timing of your vaccine may be influenced by your travel plans. If you are planning international travel, ensure that you have had a flu vaccine before leaving. If you are returning from the Northern Hemisphere in late 2021 or early 2022, it is recommended that you get a flu vaccine in the country from which you are leaving (where available) before departure.

After receiving a vaccination, including for influenza or COVID-19, some people may have unwanted side effects. Read more about when to report these side effects, and why that information is important.

The Australian Government Department of Health also has information about reporting adverse side effects following a COVID-19 vaccination - What happens after I am vaccinated for COVID-19?


Snapshot of the influenza and COVID-19 vaccines in 2021

Influenza vaccines

COVID-19 vaccines

Virus targets

Common circulating strains of influenza type A and type B.


Who is it approved for?

There are approved flu vaccines available for most people aged 6 months and older.

The Pfizer/BioNTech vaccine is provisionally approved for people aged 12 years and older.

The AstraZeneca vaccine is provisionally approved for people aged 18 years and older.

The Moderna vaccine is provisionally approved for people aged 12 years and older.

The COVID-19 Vaccine Janssen is provisionally approved for people aged 18 years and older. This vaccine is not part of the national roll out.

Are there costs?

Vaccines given through the NIP are free.

Vaccines given outside the NIP will have a charge.

Immunisation providers may have a separate consultation fee.

COVID-19 vaccines are free for everyone living in Australia.

No consultation fee will be charged.

Can I choose the brand?

Not all brands are available or suitable for all age groups (refer above).

If there is more than one brand suitable for you, selection may depend on the supply available and the advice of your vaccine provider.

Not all brands are available for all age groups.


  • the Pfizer and Moderna vaccines are recommended by ATAGI for everyone over 12 years of age.
  • the AstraZeneca vaccine is recommended by ATAGI for people aged 60 years and over.*

This could change as more information becomes available about both vaccines or if new vaccines are approved for use in Australia.

*recommendations have changed for areas currently affected by COVID-19 outbreaks - read more here.

Is this an annual vaccine?


We don’t know yet.

More clinical information is required to determine vaccination frequency.

How many doses?

One dose – for most people.

Young children aged 6 months to 9 years receiving their first vaccination may require two doses, 4 weeks apart.4

People who have recently had a haematopoietic stem cell transplant or solid organ transplant require two doses 4 weeks apart, in the first year after transplant.

Two doses.

  • At least 21 days between doses for the Pfizer vaccine.22
  • At least 28 days between doses for the Moderna vaccine.19
  • 4–12 weeks between doses for the AstraZeneca vaccine.23*

ATAGI recommends a third dose of COVID-19 vaccine as part of the primary course in individuals who are severely immunocompromised – read more here.

Booster doses are available for those 18 years and older, and for those who had their second dose of COVID-19 vaccination at least 6 months ago.

*recommendations have changed for areas currently affected by COVID-19 outbreaks - read more here.

When can I expect immunity after my injection(s)?

About 2 weeks after the injection.4

Immunity starts building after the first dose. Best possible protection starts between 1 and 2 weeks after the second dose is given.22,23

What about side effects?

Most side effects to the influenza vaccine are mild and temporary (lasting less than a week).

Common side effects include:

  • pain, redness, swelling or hardness where the needle went in (also described as injection site reaction)
  • fever, tiredness, general body aches.4

Most side effects to the COVID-19 vaccines are temporary and can be managed with rest and over-the-counter pain medicines.

Commonly reported side effects include:

  • headaches,
  • muscle and joint pain,
  • fever
  • nausea and
  • injection site reactions.22, 23

Current reports are that these symptoms are more common after the first dose of the AstraZeneca vaccine, and after the second dose of the Pfizer vaccine.24,25

A serious but very rare blood clotting syndrome has been reported following the first dose of the AstraZeneca vaccine. This condition is called thrombosis with thrombocytopenia syndrome (TTS).


Where can I find more information?

Information about flu vaccines

Information about COVID-19 vaccines

Information about vaccines and adverse events



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  2. Australian Government Department of Health. Australian Influenza Surveillance Report - week ending 05 May 2019. Canberra: DoH, 2019 (accessed 11 May 2021).
  3. Australian Government Department of Health. Australian Influenza Surveillance Report and Activity Updates. Canberra: DoH, 2021 (accessed 20 May 2021).
  4. Australian Technical Advisory Group on Immunisation. Australian Immunisation Handbook, Canberra: DoH, 2018 (accessed 11 May 2021).
  5. Therapeutic Goods Administration. Australian Influenza Vaccine Committee (AIVC). Canberra: DoH, 2020 (accessed 18 May 2021).
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  7. Therapeutic Goods Administration. Flublok Quadrivalent. Canberra: DoH, 2021 (accessed 21 May 2021).
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  10. National Center for Immunization and Respiratory Diseases. SARS-CoV-2 Variant Classifications and Definitions. USA: Centers for Disease Control and Prevention, 2021 (accessed 19 May 2021).
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  12. Kustin T, Hare N, Finke U, et al. Evidence for increased breakthrough rates of SARS-CoV-2 variants of concern in BNT162b2 mRNA vaccinated individuals. [Preprint] medRxiv 2021.04.06.21254882
  13. Haas EJ, Angulo FJ, McLaughlin JM et al. Impact and effectiveness of mRNA BNT162b2 vaccine against SARS-CoV-2 infections and COVID-19 cases, hospitalisations, and deaths following a nationwide vaccination campaign in Israel: an observational study using national surveillance data. Lancet: 397; 1819-29.
  14. Wu K, Choi A, Koch M, et al. Preliminary analysis of safety and immunogenicity of a SARS-CoV-2 variant vaccine booster. [Preprint] medRxiv 2021.05.05.21256716
  15. Emary KRW, Golubchik T, Aley PK, et al. Efficacy of ChAdOx1 nCoV-19 (AZD1222) Vaccine Against SARS-CoV-2 VOC 202012/01 (B.1.1.7). Lancet 2021:397;1351-1362
  16. Townsend JP, Hassler HB, Wang Z, et al. The durability of immunity against reinfection by SARS-CoV-2: a comparative evolutionary study. Lancet Microbe. 2021;2:e666-e675.
  17. Pfizer Inc. Pfizer and BioNTech confirm high efficacy and no serious safety concerns through up to six months following second dose in updated topline analysis of landmark covid-19 vaccine study. Press release 1 April 2021(accessed 21 May 2021).
  18. Doria-Rose N, Suthar MS, Makowski M, et al. Antibody persistence through 6 months after the second dose of mRNA-1273 vaccine for Covid-19. New Eng J Med 2021; 6 April. doi:10.1056/NEJMc2103916
  19. Australian Technical Advisory Group on Immunisation. Clinical guidance on the use of COVID-19 vaccine in Australia in 2021 (v7.0) Canberra; DoH, 2021 (accessed 23 August 2021).
  20. NSW Health. Residential care facilities and influenza - Influenza. Sydney: NSW Government Department of Health, 2021 (accessed 12 May 2021).
  21. Queensland Health. Residential aged care communication. Seasonal influenza – are you ready? Brisbane: Queensland Government Department of Health, 2021 (accessed 17 May 2021).
  22. Pfizer Australia Pty Ltd. Comirnaty COVID-19 Vaccine Approved Product Information. Sydney: Pfizer Australia Pty Ltd, 2021 (accessed 11 May 2021).
  23. AstraZeneca Pty Ltd. COVID-19 Vaccine AstraZeneca Approved Product Information.. Macquarie Park: AstraZeneca Pty Ltd, 12 May 2021.
  24. Australian Government Department of Health. Are COVID-19 vaccines safe? Canberra: DoH, 2021 (accessed 21 May 2021).
  25. Therapeutic Goods Administration. COVID-19 vaccine weekly safety report – 20-05-2021. Canberra: DoH, 2020 (accessed 22 May 2021).