Kathy Smith and her family were just days away from getting their annual flu vaccines when the virus hit and caused chaos.
First her six-year-old daughter Ada came down with fatigue, then suddenly developed chills and a high fever which lasted days.
In the week that followed everyone in the family became infected, including her five-year-old sons Albert and Arthur, who both had fevers, vomiting, and heavy coughing.
Ms Smith said the illness was "brutal" and "violent", taking the family out of work and school for up to two weeks each.
"The kids generally haven't had anything that full on before," she said.
"We've had lots of random viruses and stuff, but never like this."
Healthcare workers are warning that young children could be at risk this year amid low vaccination rates and the flu season starting earlier than usual.
Reported flu cases have more than doubled in the past five weeks, climbing from about 32,000 at the end of April to more than 68,000 cases as of yesterday.
Children under 10 are getting infected at much higher rates than other age groups, and more than 300 children under 16 have been admitted to hospital, the latest national surveillance report shows.
Asha Bowen, a paediatric infectious diseases specialist at the Perth Children's Hospital, said doctors were seeing a "very early and quick upswing" in flu cases affecting children under 10.
"We're seeing a lot more kids coming through with influenza admitted into our children's hospitals and seeing GPs and emergency departments for care," Dr Bowen said.
"Whilst flu is something that usually hits every winter, we haven't seen these kinds of peaks since COVID occurred.
"It's taking parents, healthcare providers and others by surprise to have flu return at such rates."
Why young children are 'very vulnerable'
Low immunity from the COVID years is one reason why children could be more at risk this flu season, experts say.
Both childhood vaccination rates and exposure to the flu dropped during the pandemic, leaving many young kids exposed for the first time this year, said Margie Danchin, a paediatrician and immunisation expert from the Murdoch Children's Research Institute.
"Young children are very vulnerable, with low immunity to the flu and other viruses like RSV, which is also increasing earlier this year," Professor Danchin said.
And with cases of COVID, RSV and flu – known as the "big three" — rising at the same time, doctors were concerned about the effects getting multiple respiratory infections could have on children, Professor Danchin said.
Childhood vaccination numbers dropped globally during COVID and haven't yet recovered to pre-pandemic levels. Australia was no exception.
Since March, only 17 per cent of children under five have had the latest flu vaccine, compared with 38 per cent by the same time of year in 2020, data from the National Centre for Immunisation Research and Surveillance shows.
Concerns about low childhood vaccinations this year even prompted the national chief medical officer Paul Kelly to write to GPs, encouraging them to try to turn things around.
The flu vaccine is free from pharmacies and GPs for high-risk groups including children under five. Children under six months cannot get vaccinated against flu, so it is free for pregnant women to help provide immunity to the unborn child.
A recent poll shows while many parents have good intentions, most have not gotten around to it.
'Don't underestimate the flu'
While nearly two-thirds of parents planned to get their children vaccinated against the flu this year, only 11 per cent had actually done it, the Melbourne Royal Children's Hospital flu poll found.
"The intention to take up the flu vaccine for children, particularly young children, is actually higher this year than it has been in previous polls. But at the same time, the actual actioning of that is down," said Anthea Rhodes, a paediatrician and the poll's director.
"It suggested to us that people perhaps have logistical barriers and issues … getting around to it."
A large proportion of parents also feel unsure about getting the flu vaccine or flat out don't want it, the poll found.
Misconceptions about the vaccine were common among hesitant parents, as well as "vaccine fatigue", or feeling like kids have had too many vaccines in recent years, Dr Rhodes said.
About 70 per cent of hesitant parents did not know a new flu vaccine was needed each year to stay protected, the poll found.
"Even though it's hard to get around to getting it done, it's a lot more difficult to face a serious infection in your young child," Dr Rhodes said.
Kathy works in healthcare, so is diligent about making sure her family get their flu jabs every year in early May.
But after a difficult few weeks, Kathy says in future they will get them in April just in case flu season strikes early again.
"Don't underestimate the flu, it's not a cold," she said.
