Dr Nick Coatsworth used to be the face of the COVID-19 vaccine rollout, but even he is guilty of putting off getting the flu jab.

The infectious diseases physician came down with a nasty bout of influenza last year and wishes he was protected sooner.

"I can't remember why I delayed it, but it was the end of April by the time I thought about it and it was too late, I actually got the flu," Dr Coatsworth told AAP.

The former deputy chief medical officer had to take a week off work and is now on a mission to make sure no one else makes the same mistake this year.

"It is number one on my to-do list," he said.

There have been more than 10,300 reported influenza cases over the first 10 weeks of 2023, with about one-quarter of cases in children aged nine or younger.

It is hard to predict just how serious the upcoming flu season will be, but it was particularly bad during the northern hemisphere winter, and Dr Coatsworth believes cases could spike as international travel ramps back up.

Respiratory syncytial virus (RSV), flu and COVID round out the virus triple threat looming over coming months.

"Flu is a bit different to COVID because younger Australians, in particular those aged six months to five years, can be significantly impacted, as well as older Australians," Dr Coatsworth said.

"Then middle-aged Australians, working-aged adults, they can be taken out of work by influenza."

It can also lead to hospitalisation, which Brisbane mother Niroshini Senanayake found out the hard way.

She didn't get the jab and ended up spending four days in hospital.

"I had no energy, I couldn't even lift my arm up," Ms Senanayake said.

"It was terrible, to be really honest. One thing was I had to make sure that (her son) didn't catch it."

She requires ongoing blood tests to monitor her health and will roll up her sleeve this year to avoid becoming that sick again.

"It's just protecting everyone, starting from your household," Ms Senanayake said.

Flu vaccines are free for children aged six months to five years, those aged 65 or older, pregnant women, patients with certain medical conditions, and Aboriginal and Torres Strait Islander people, under the national immunisation program from April.

Jabs can be given at GP clinics, pharmacists, community health centres and many workplaces. They are also available to buy privately.

TerryWhite Chemmart chief pharmacist Brenton Hart says while vaccine fatigue is setting in for some, the flu mutates, so it is important to get protected each year.

"We're here to help people make informed decisions about vaccinations so we can have that discussion, help debunk any myths, and help you be protected for the cooler months ahead," he said.