Australia’s winter illness season is back – what viruses are prevalent this year and when should you get vaccinated?

As of 4 June, the national notifiable diseases surveillance system has been notified of 33,559 influenza cases, 40,054 Covid-19 cases and 50,572 cases of RSV, short for respiratory syncytial virus. Photograph: David Cheskin/PA

Australia began the year grappling with an unseasonably high rate of influenza infections, driven by a mutation of the H3N2 strain of the influenza A virus that emerged in 2025.

While no more severe than other strains, subclade K – which some dubbed “Super-K” because of its infectiousness and subsequent rapid spread – saw thousands of summer flu cases.