Unusual flu trend sees South Australia cases spike later than expected

South Australia's health experts are observing an "unusual" flu trend this year, with a noticeable increase in cases only beginning in August, well after the typical winter peak.

“

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.

"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," said SA's Chief Public Health Officer Nicola Spurrier. She noted that last year also saw an atypical pattern, with a second wave occurring in October and extending into the summer.

Professor Spurrier suggested that a strain from the northern hemisphere, dubbed the "Super K" strain, contributed to the summer wave in Australia last year. This, she believes, may have provided the population with some immunity, but this immunity naturally wanes over time.

“

The most likely reason for that is, last year was again an unusual year.

Local general practitioner Daniel Byrne corroborated the observation of lower flu cases this winter, estimating them to be about ten times less than in previous years. He also pointed to the changing global landscape, with increased international travel potentially leading to more flu cases during Australia's summer, a significant shift from patterns observed 15-20 years ago. Byrne advised that it is "still not too late to get your flu shot because the flu could still be coming later this year."

“

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.

Beyond the flu, doctors are busy managing other respiratory illnesses, primarily rhinovirus (the common cold) and RSV (respiratory syncytial virus). Byrne expressed a desire for expanded eligibility for the free RSV vaccine, noting that while pregnant women, newborns, and adults over 75 currently have access, he would like to see similar provisions in South Australia.

“

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.