'Unusual' flu trend with SA cases to spike later than expected

'Unusual' flu trend with South Australian cases to spike later than expected, health chief says Sun 9 Aug 2026 at 7:12am In short: SA's Chief Public Health Officer says the number of flu cases in the state have only started to rise in the past few weeks as population immunity "wanes". But an Adelaide doctor says other respiratory illnesses have kept health workers busy. What's next? Health experts say it is not too late to ask for the flu jab, with cases expected to rise later than usual. An "unusual" flu trend will likely see more people sneezing and reaching for their tissues after the peak winter season, South Australia's health experts say. SA's Chief Public Health Officer Nicola Spurrier said the number of flu cases have only just started picking up in the last few weeks in the state. "We've had an unusual year, because we've only just started to see the flu numbers tick up — and look at us, we're in August," Professor Spurrier said. "The most likely reason for that is, last year was again an unusual year. "We had the standard peak right in the middle of winter… and then we saw a kick up around about October, going into summer we had another wave." Professor Spurrier said the subclade K strain from the northern hemisphere, otherwise known as the "Super K" strain, contributed to the second wave of summer cases in Australia. "What I think that's done is give our community at a population level — some immunity to flu, but with infectious diseases over a period of time — population immunity wanes,"Professor Spurrier said. Adelaide general practitioner Daniel Byrne said this year's flu cases were about 10 times less compared to previous winters. "The world's changing … international travel, the spread of viruses around the world — when it's winter in the northern hemisphere it's summer here, perhaps we're getting more flu in our summer which is a total change from 15-20 years ago," Dr Byrne said. "We might be in for a late season, so the big advice is, it's still not too late to get your flu shot because the flu could still be coming later this year." Dr Byrne said other respiratory illnesses were keeping doctors busy. "We're getting a lot of rhinovirus, which is the common cold — that's probably number one, the second would be RSV [respiratory syncytial virus]," he said. So far this year, South Australia has recorded 5,702 cases of RSV, an illness that is highly contagious and is a common cause of hospitalisation in young babies. Protecting against RSV Dr Byrne said he would like to see expanded eligibility for the free RSV vaccine. Pregnant women have had free access to the RSV vaccine under the National Immunisation Program since February 2025. Newborns who did not receive protection during their mothers' pregnancy were eligible for the monoclonal antibody nirsevimab through state and territory-funded programs. In May this year, adults over 75 became eligible for the free vaccine, which can cost up to $350, the WA government has expanded eligibility to include those aged 65 and older living in residential aged care. Dr Byrne said he would like to see the same in SA. "Personally, as a doctor in South Australia I would love to be able to give those vulnerable people an RSV vaccine, and save the health system a huge amount of money as well," he said. Professor Spurrier said health authorities would be watching RSV case numbers in the year to come. "Let's see how we go with this year and review those results, we always make comparisons of course we do when we look at epidemiology between states," she said.