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Australia’s latest national epidemiological update shows COVID-19 activity has decreased since the June 2025 peak and remains lower than at the same time in 2024. RSV activity remains low, as expected for this time of year.
Flu activity has been rising since late October – unusual for the time of year – before declining sharply in the final weeks of 2025.
This increase likely is driven by influenza A(H3N2) subclade K, which emerged in Australia from August, and has spread rapidly since then.
Health care (and testing) can be harder to access during the holiday period, which could be the reason for such a sharp decrease at the end of December. We are watching closely to see whether the decrease continues.
This is the first time that a new influenza A(H3N2) strain has emerged and spread so widely towards the end of the season in Australia.
The data does not predict future activity, and does not indicate a change in public health advice.
It is a reminder that no two influenza seasons are the same, and that ongoing virus evolution requires continuous national surveillance and analysis.
The Australian Respiratory Surveillance Report provides a snapshot of current trends in respiratory infections, including COVID-19, influenza and RSV. This is the first time it has been published under the auspices of the new Australian CDC.
The CDC continues to monitor respiratory illness and infections through multiple national surveillance systems to support preparedness, planning and informed public health decision-making.
Read the latest Australian Respiratory Surveillance Report.
Vaccination continues to reduce the risk of severe illness, particularly for older people and those at higher risk. Find out more about protecting yourself and your family from respiratory disease across the seasons.