Baby Clementine was burning with fever, coughing and sleeping almost around the clock.
Her parents, Emily Ritchie and Lachlan Barnes, had no idea their 15-month-old had fallen ill with the flu.
Like more than two-thirds of Australian parents, they hadn't immunised their daughter against the potentially deadly virus.
The Royal Children's Hospital has seen an alarming increase of almost 50 per cent in flu cases so far this season compared with last year.
So far, 101 children have been diagnosed by the hospital with the illness, many of them admitted to intensive care, compared with 69 before the end of July in 2016.
In what flu experts are finding is a disturbingly common problem, a doctor had incorrectly told Clementine's parents that children don't need the flu shot.
This is despite a federal recommendation that all children over six months should have one. And despite the virus killing children or causing them permanent brain damage each year.
Mr Barnes said they were disappointed with the contrary advice being handed out.
"There's a bit of outrage with some of our mates," he said. "They've had similar cases where they've asked for vaccinations and they haven't been given them."
Poor information about flu vaccination for children had contributed to the more severe flu season, Dr Margie Danchin said.
The flu expert, who oversaw Clementine's treatment, said doctors giving incorrect advice was a huge problem.
"One of the biggest feedback we get from parents is 'My GP told me not to get the flu vaccine for my child'," she said.
"The strong message that we get is that GPs tell them not to get the flu vaccine if their children are under five, when in fact the [correct] message is the complete opposite."
Dr Danchin said children aged from six months to five years were in a high-risk group.
Up to 10 per cent of children who end up in hospital can have neurological problems, such as memory loss, seizures, and learning and speech difficulties, she said.
A poll released by the hospital this year found almost nine in 10 parents were unsure about the safety of the flu vaccine.
One in six thought the flu wasn't a dangerous disease, while more than a quarter believed healthy children could not get seriously ill from it.
Other parents wrongly believed children could get the flu from the vaccine, while others didn't believe it worked.
Baby Clementine's parents called for better information about the vaccine for parents and doctors.
They feel incredibly lucky she didn't have any major complications.
"Just hearing about that, it's scary," Mr Barnes said. "We're relieved she's on the mend."