Flu Surpasses COVID-19 as Leading Respiratory Threat in Australia
Australia is experiencing a significant shift in the landscape of respiratory illnesses, with influenza now surpassing COVID-19 as the primary cause of death from acute respiratory infections. Data released on Tuesday, February 24, 2026, by the Australian Bureau of Statistics (ABS) reveals a concerning trend: 2025 saw the highest number of influenza-related deaths this century, totaling approximately 1,701.
A Dramatic Reversal: Flu Takes the Lead
For the past two years, COVID-19 dominated the statistics for respiratory-related fatalities. However, 2025 witnessed a sharp decline in COVID-19 deaths – falling by more than half to 2,161, compared to 5,108 in 2024. Simultaneously, influenza cases surged, exceeding COVID-19 related deaths from August 2025 onwards. Between August and December 2025, there were approximately 741 influenza deaths, compared to around 428 COVID-related deaths.
The Rise of Subclade K
Epidemiologist Catherine Bennett of Deakin University attributes the increased severity of the flu season to the emergence of a modern flu variant, H3N2 Subclade K. “The H factor, the Hemagglutinin protein, had a number of different mutations in it that we hadn’t seen before,” she explained. This mutation meant that existing vaccines and prior immunity were less effective, contributing to a prolonged outbreak extending into the summer months – an unusual occurrence.
COVID-19: A Shift Towards Seasonality
While influenza is currently the more pressing concern, the ABS data indicates that COVID-19 is evolving into a more seasonal virus, with peaks typically occurring during the winter months. Professor Bennett noted that COVID-19 remains a significant threat during winter, responsible for more deaths than influenza during that period. However, for the first time, the summer months saw a considerably lower impact from COVID-19 in terms of fatalities.
RSV Remains a Factor
Respiratory Syncytial Virus (RSV) also contributed to the burden of acute respiratory infections, with approximately 582 deaths reported – about a hundred more than in 2024. This highlights the importance of considering multiple respiratory pathogens when assessing public health risks.
Vaccination Rates: A Critical Concern
A significant factor contributing to the severity of the 2025 flu season is low vaccination rates. Only around 60% of individuals over the age of 65 were vaccinated against the flu. Professor Bennett emphasized the vulnerability of this age group and the importance of increasing vaccination coverage to protect those most at risk of severe illness and death.
Looking Ahead: What Does This Mean for the Future?
The shift in dominance from COVID-19 to influenza underscores the dynamic nature of respiratory viruses. While COVID-19 hasn’t disappeared, its impact appears to be lessening, potentially settling into a seasonal pattern. However, the emergence of new influenza variants, like Subclade K, demonstrates the virus’s ability to evolve and evade immunity. This highlights the need for ongoing surveillance, vaccine development, and public health preparedness.
FAQ
Q: Is the flu vaccine effective against the new Subclade K variant?
A: While the vaccine may not be a perfect match, it can still reduce the severity of illness and the risk of complications.
Q: Is COVID-19 still a threat?
A: Yes, COVID-19 remains a significant respiratory virus, particularly during the winter months.
Q: What age group is most vulnerable to severe respiratory illness?
A: Individuals over the age of 70 are at the highest risk of severe illness and death from COVID-19, RSV, and influenza.
Q: Why were there more flu deaths in 2025 than in previous years?
A: The emergence of a new flu variant (H3N2 Subclade K) and lower vaccination rates contributed to the higher number of flu deaths in 2025.
Did you know? 2017 previously held the record for the highest number of influenza-related deaths this century, with approximately 1,656 deaths recorded.
Stay informed about respiratory health and take proactive steps to protect yourself and your community. Explore the Australian Department of Health website for the latest updates and recommendations.
