Push for COVID-19 booster vaccines as Australia heads into 'uncertain' winter

That warning comes after variants EG.5 (Eris) and JN.1, responsible for a double-strain wave at the end of 2023, become less virulent in Australia.

"It might be end of April or even May before we really start to see a rise again," Deakin University chair of epidemiology Catherine Bennett said.

"What would trigger that would probably be a new variant," she said.

Public health experts are watching for new variants of the virus internationally as "a signal that we can expect the same," Professor Bennett said.

But no such variants have caught their attention.

JN. 1 remains Australia's dominant variant based on wastewater reports from NSW and Victoria.

A long break from a JN.1 COVID-19 peak could mean people are susceptible to reinfection with the variant, Professor Bennett said.

She recommends a booster shot for those who haven't been infected with COVID or vaccinated for more than six months to improve immune response.

"Over the next two to four weeks is the right time because it can take a couple of weeks to get the benefit of a booster," Professor Bennett said.

Surveillance systems and strong public health communication remains crucial as people learn to live with the endemic virus, the chair of epidemiology said.

"Health departments will let people know when the risk is starting to shift again," she said.

"Knowing that information is really powerful, it gives people the opportunity then to respond to that change in their own risk situation," she said.

"It's important we do everything we can to minimise those harmful impacts and that does come back to us as individuals, managing our risk and managing the risk we might pose to others."

Australia's Christmas wave caused fewer deaths and hospitalisations compared to previous peaks.

Professor Bennett attributes the falling death toll to a combination of factors.

"It's possibly about the variants themselves becoming slightly less severe but a lot of it is about the population immunity," she said.

"With each wave of infection, even if you're not infected, you're brushing up against exposures in the community.

"It means with each wave, there's been a bit more resilience, a bit more of a mature immune protection across the community."