Extraordinary case numbers have been recorded in first two weeks of the year in a continuation of the unusual interseasonal trends of 2025.
There were more than 500,000 laboratory confirmed influenza cases in the country in 2025, compared to 365,000 the previous year and 290,000 in 2023.
Already in the first 15 days of 2026, the National Notifiable Disease Surveillance System has recorded more than 7100 cases.
“It’s a big jump from the previous year, which was a big year in itself,” said Associate Professor Paul Griffin, Director of Infectious Diseases at Mater Health and Principal Investigator and Medical Director at Nucleus Network.
“The other very unusual thing about the flu in Australia in 2025 was how much flu we saw in the usual interseasonal period in the summer months.
“We started the year with a lot of flu in summer, which was unusual, and ended the year with an extraordinary amount of flu still going around. And that continues to this day.”
He explained that the proportion of tests that were positive in 2025 were quite high, suggesting that an increase in testing is not necessarily the explanation.
“I wouldn’t suggest that what we’ve seen this year is just a manifestation of increased testing. I would say that, in fact, it might actually be a little bit the opposite,” Professor Griffin told The Medical Republic.
“People are testing at home as well … and we don’t collect those figures, so that may actually also contribute to the fact that there’s probably a lot more out there, because the cases we’re talking about are those laboratory-confirmed cases.
“The only thing that we know is certain with the flu is one of the key drivers of what we saw last year was the emergence of subclade K.”
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He explained that this new strain, part of the H3N2 family, had changed quite significantly, which meant past infections and vaccines provided less protection.
“Vaccines have been updated, so whether that means we return to a more usual type of season remains to be seen. We’ll see what happens once our updated vaccine rolls out,” he said.
“Of course, the main thing that’s going to determine how well that works is uptake. And our uptake last year was terrible. We really need to address that if we want to try and get things back under better control.”
Professor Griffin is hopeful that the state-funded intranasal flu vaccination programs starting this year will boost uptake in children.
“FluMist is going to be great. It’s a fantastic vaccine. It’s had a checkered past in some years – it didn’t seem to perform that well. But we have to remember, the flu vaccine is variable in its performance every year because of how much the flu can change,” he said.
Needle phobia, especially in young children, may be a major contributing factor to low vaccine uptake, said Professor Griffin, with some studies suggesting needle phobia may be present in up to a third of kids.
“A vaccine we can administer that doesn’t rely on needle and syringe is going to potentially be huge,” he said.
These intranasal flu vaccination programs, announced in South Australia, New South Wales and Queensland, promise a free alternative to the annual jab for children aged between two and five.
Western Australia went a step further, announcing FluMist funding for children up to 12 years of age.
Victoria, the Northern Territory and Tasmania have not yet responded to calls from the RACGP to fund Flumist programs.
A spokesperson for NSW Health told TMR that the intranasal vaccine would be available in late March/April 2026, in line with the release of all other influenza vaccines.
“In NSW, supply of the new vaccine will cover approximately 40% of eligible patients, offering an alternative option for families to help improve vaccination uptake in the lead up to the 2026 winter flu season,” they said.
