The Univeristy of Melbourne The Royal Melbourne Hopspital

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06 Mar 2023

The upcoming 2023 influenza season in Australia – What’s to come?

An article written by The Royal Melbourne Hospital Professor Ian Barr, Deputy Director of the WHO Collaborating Centre for Reference and Research on Influenza at the Doherty Institute.

Speculating on the intensity of influenza seasons in advance is always challenging as the influenza seasons vary considerably from one season to another. There is a saying by those people who work in the field that “If you have seen one influenza season, then you have just seen one influenza season” – meaning that one cannot draw too much confidence by simply observing what happened in the previous season. This is even true when looking to the Northern Hemisphere’s most recent season which is now coming to an end as March begins.

Coinciding with the end of their season the World Health Organization (WHO) has recently made a recommendation for the components for the next Northern Hemisphere 2023-2024 influenza vaccine.

The reason why these recommendations need to be made some 8 to 10 months before the influenza season is because of the lead time to make and roll-out vaccines in time.

One item of interest in this 2023-2024 decision, was the change to the A(H1N1)pdm09 component of the vaccine to a reference virus called A/Victoria/4897/2022. This means that all of the influenza vaccines produced for the 2023-2024 season will contain a derivative of this virus or a similar “like” virus. This virus was originally obtained from a clinical sample provided by the Royal Melbourne Hospital pathology laboratory and isolated at the WHO Collaborating Centre for Reference and Research on Influenza at the Doherty Institute.

So, back to what our influenza season might present to us in Australia in 2023.

One thing for certain is that there will be an influenza season, unlike 2020 and 2021 when COVID-19 and its many restrictions severely affected influenza circulation. In 2022, influenza returned with a vengeance and will again circulate widely in 2023.

When the season will start is uncertain. Prior to the pandemic, cases usually increased through May, peaked in August, then waned in October. But this timing may be altered due to COVID-19. In addition, given the difficulty in predicting the severity of the season, it’s again recommended that certain people get vaccinated each year especially the elderly, children under 5 years old, pregnant women, indigenous people and those with underlying health conditions.

So, if you want to protect yourself against influenza this year, even if you are not in one of these groups, consider getting an influenza vaccination in 2023.