Health experts are warning Australians to brace for a triple threat this winter, as COVID-19, influenza, and RSV continue to spread rapidly. The strongest protection, they say, is timely vaccination—ideally before the end of May.

“We’re already seeing an early wave of highly infectious respiratory illnesses,” said Professor Paul Griffin on Wednesday. “When one person in a household gets sick, the virus can spread to everyone within days. Early detection is key to managing outbreaks and protecting vulnerable groups.”

As of May 22, more than 80,000 flu cases have been confirmed across Australia—a more than 50% increase from the same time last year. Influenza, typically caused by type A or B viruses, is a highly contagious respiratory infection with several subtypes and strains.

COVID-19 cases are also expected to surge in the coming months, driven largely by a highly transmissible Omicron subvariant known as LP.8.1. This strain was responsible for 60% of COVID cases in the UK by March and has been linked to significant outbreaks overseas since late 2024. While not more severe than previous strains, it appears to spread more easily.

Professor Catherine Bennett, an epidemiologist at Deakin University, emphasized the importance of staying current with COVID vaccinations—especially for those over 65 or with underlying health issues.

“Vaccines take a couple of weeks to become effective and typically offer protection for a few months—which is the length of most seasonal waves,” she said. “Getting vaccinated in May ensures you’re protected during the peak period. Don’t wait for cases to climb—act early.”

She warned that multiple factors are contributing to the anticipated spike in infections: waning immunity, lower booster uptake, and more people gathering indoors as temperatures drop.

“This variant has been in Australia since July last year, but as we moved out of winter, most people still had recent infections or booster protection. That’s no longer the case,” she noted.

Professor Griffin stressed the importance of keeping up to date with vaccinations and using rapid antigen tests to prevent the spread of viruses within households.

“Infants, older adults, pregnant women, and people with chronic health conditions are most at risk of severe complications, including pneumonia, dehydration, and hospitalisation,” he said.

“Recognising symptoms like high fever, fatigue, wheezing, and difficulty breathing early allows for timely action—whether it’s starting antiviral treatment, isolating, or seeking urgent care. Early testing benefits not only individuals but public health at large.”

Despite the risks, vaccination rates declined last year by nearly 6% across all states and territories.

Both COVID and flu vaccines are available free of charge in Australia, even for those without a Medicare card. Vaccines can be accessed through various providers—use the Healthdirect service finder to locate one near you.

So far in 2025, New South Wales has reported the highest number of flu cases (31,995), followed by Queensland (18,818) and Victoria (17,618). Western Australia has recorded 6,510 cases, with South Australia (4,719), Northern Territory (1,557), Tasmania (1,126), and ACT (1,099) trailing behind.