Australia's deadliest flu outbreak has left researchers scrambling to find out the causes of this year's vicious season.
Australian hospitals are overrun with patients struck down by this season's vicious flu outbreak and flu-related deaths continue to worry.
The flu season started early this year after a mild 2018, leading to significantly higher numbers of cases that are usually experienced by this point.
Nearly 217,000 Australians have been diagnosed with influenza so far this year, a dramatic increase across the country leaving state and territory health departments urging people to seek medical help if they feel unwell.
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The national death toll seats at 430 and experts believe the real figure to be much higher, saying some deaths were attributed to other causes despite showing many flu-related symptoms.
Krispin Hajkowics, the Director of the Hospital's Infectious Diseases Unit, said he's never seen a flu season like it, the ABCreports.
"We've all been working very hard. The hospitals have been dealing with very large numbers of cases of influenza through the emergency department, the general wards and the intensive care units."
This year the flu season started earlier than previous years, which saw the number of patients contracting the deadly virus reach its peak between June and September.
A report released by the World Health Organization Influenza Center said the number of cases was about "five times what we'd normally see in that inter-seasonal period," report author Professor Ian Barr said.
"2019… may actually exceed the 2017 season."
Researchers have been left racing to find out why this year has been vicious, some experts think a link between climatic factors could explain the increase in reported cases.
"We can't explain 100 per cent why, when it's over 25 degrees Celsius, why we have a sharp increase," Dr Jianyun Lu told the ABC.
The unusual amount of children hospitalized with flu symptoms over the summer has become a new focus for experts who are investigating whether certain factors were helping the virus to transmit easily and survive for longer.
"By the end of the year, I think we'll have a good understanding of potential factors that could have contributed to our unusual summer flu," Dr Kirsty Short told the publication.
Australia's deadly flu outbreak left a young girl partially paralyzed in intensive care after she contracted the flu in June.
Hayley Henwood, 3, was "ravaged" by the flu virus then hit with secondary infections that attacked her brain and left her "partially paralyzed," Nine News reported.
The young girl now faces months of rehabilitation and physiotherapy as she learns to walk and talk for the second time in her short life, after spending weeks in hospital.
According to Emma Henwood, her daughter's recovery time will be slow and steady.
"Talking to her is a little bit delayed," she said.
"She has to think about what she's saying, and ask her questions like 'what's wrong?' is a bit open-ended for here at the moment.
Authorities are urging people to get their flu shots as this season's flu crisis continues to spread across the nation leaving a soaring death toll in its wake.
"The best weapon against flu is vaccination," NSW Health's Director of Communicable Diseases, Dr Vicky Sheppeard, said.
"Children are particularly susceptible to flu parents and carers are being urged to take up the offer of the free flu vaccine for children aged six months up to five years under the NSW Government's $ 2.6 million program.
"There are ample supplies of influenza vaccine and we urge parents of children under 5 years of age and others vulnerable to influenza to visit their GP as soon as possible."