‘Super-K’ influenza strain big contributor to record flu season with West Australians urged to get protected

January brought a reprieve after a record flu season for WA last year but the start of the school year has experts urging families to get protected against the infectious disease. The State had a record flu season in 2025 with a total of 36,621 cases — the previous record was in 2019 when WA recorded 23,248 infections. Flu cases are remaining below the usual seasonal threshold in WA so far this year and figures are much lower than at the start of 2025. There was more than 800 cases of the flu in WA by the end of January while the same month last year the State had already recorded almost 1200 infections. However, with cases across the rest of the nation still remaining just as high as last year Perth Children’s Hospital paediatrician and Kids Institute vaccine researcher Chris Blyth has urged West Australians to get vaccinated this year in an effort to minimise the spread. “Lots of flu last year means that there’s probably some immunity so therefore January being low is not that surprising at this stage, so a bit more of a normal January this year,” he said. “Flu is unpredictable and it’s also very susceptible to population movements and mixing so there’s always the risk, particularly as kids go back to school, that our influenza rates continue to climb. “What we do know also is clearly flu will increase significantly in our winter months and that’s why we need to get prepared ahead of that.” A fast-moving strain nicknamed the ‘Super-K’ flu — known as Subclade K in the H3N2 influenza family — was to blame for a longer and record flu season in 2025. A WA Health spokesperson said the subclade K strain was first detected in WA in August 2025 and was a “contributor to a prolonged influenza season”. Mr Blyth urged all West Australians to get vaccinated against the flu this year when they become available for free, which is usually around April. A new nasal spray will also be rolled out for children under 12 this year in a bid to boost flu vaccination rates, which only sat at 15.3 per cent for five to 15-year-olds in WA in 2025. “Vaccination is the most effective way to try and protect against flu,” Dr Blyth said. “Hundreds of children and adults are admitted to hospital every year with flu and we do see flu related deaths every year in both children and adults so getting vaccinated is still the most important way to protect against that. “The opportunity to have a needle-free influenza vaccine will be made available to West Australian young children this year and we certainly hope that parents take up that recommendation to try and protect them and the community against the flu.” The 2026 influenza vaccine for Australia is expected to provide a higher level of protection against the subclade K strain. “Western Australians are encouraged to plan ahead and book their influenza vaccination early,” a WA Health spokesperson said. “The best time to be vaccinated is between April and May, so immunity has time to develop before the winter influenza season. “WA has previously recorded higher-than-usual case numbers early in the year, reinforcing the importance of early preparation.”