HEALTH authorities will today issue an urgent plea for Queenslanders to make sure they are vaccinated, with a summer flu causing an alarming surge in out-of-season cases.

More than 1700 Queenslanders were last month confirmed with influenza, nearly double the cases reported during the same period for the past five years.

The extraordinary spike in cases of the potentially deadly illness has shocked experts who said this winter was one of the best flu seasons in previous years.

Health Minister Steven Miles said despite having a mild flu season, cases in November were unusually high.

"Not only did we avoid a repeat of 2017, which was one of the worst years for flu on record, but we are set to report the lowest number of cases since 2013," Mr Miles said.

More than 14,000 cases have been confirmed so far this year, well down on previous years, including last year when more than 56,500 cases were notified.

September recorded the most cases of flu this year with 2484 Queenslanders struck down.

Authorities have urged people to make sure they are vaccinated. Picture: iStock
Authorities have urged people to make sure they are vaccinated. Picture: iStock

UQ influenza expert Dr Kirsty Short said while summer flu spikes were not common they did occur.

Last year a summer flu outbreak in Hong Kong killed more than 200 people.

"There's a few reasons why they happen, it could be that it's a strain of the virus not covered by the vaccine … influenza is a virus that can evolve quite quickly," she said.

"Another problem can be that sometimes the vaccine protection begins to wane. One of the problems we had in 2017 was people getting vaccinated early in the season because the season went longer than normal the protection waned over time."

Dr Short said weather conditions could also play a part.

"Temperature contributes to the ability of the virus to survive in the environment," she said.

More than 1.2 million government-funded flu vaccines were distributed across the state this year.

The Department of Health is urging pregnant women to make sure they are up to date with their flu vaccinations.

"I'd also encourage people to continue practising good health hygiene like washing hands regularly, covering a cough with a tissue or arm, and staying at home if they're ill," he said.

"There was extraordinarily high demand for the vaccine by people of all ages this year and that is what we want to see because vaccination is by far the best protection against influenza."