No peak: Australia bucks a years-long winter sickness trend

Australia appears to have avoided the winter surge in COVID-19 cases seen in previous years, with experts pointing to changing virus behaviour and population immunity as possible explanations.

Federal surveillance data shows 64,357 COVID-19 cases have been reported so far this year, 56 per cent fewer than the 146,232 cases recorded over the same period in 2025.

The latest figures paint an unusual picture of Australia's COVID-19 landscape, with infections remaining well below last year's levels even as cases begin to tick upwards across the community.

Professor Catherine Bennett, chair of epidemiology at Deakin University, said the absence of a clear winter peak was significant.

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She said Australia's experience reflected a population that had gradually developed greater immunity to the virus through previous infections and vaccination.

"When you have variants that stay in circulation for a longer period of time, more people have had their immunity naturally boosted against that variant, and that then keeps infection rates down," she said.

Bennett said having fewer major changes in the variants circulating than earlier in the pandemic may be helping people's existing immunity provide greater protection against severe infection.

Rather than a substantially different variant emerging every few months in Australia, the same dominant variant was continuing to circulate, allowing immunity in the population to remain "primed".

Epidemiologist professor Adrian Esterman told SBS News that the pattern of COVID-19 outbreaks had changed significantly over the past few years.

"We aren't actually seeing waves anymore, or if we do have waves they're very small ones," he said.

Esterman said smaller increases in cases now tended to coincide with the emergence of a variant that was better able to transmit or evade existing immunity.

The experts said that a major change to the virus's genetics could still trigger a larger wave, but said there was currently little evidence of one developing.

"Unless there's a huge genetic shift in the virus ... that's the only thing that could disrupt things and cause another wave," Esterman said.