The late start to wintry weather has meant a late start to the flu season - but now it's here in full force.
NSW Health has issued a warning for the elderly to be on high alert for influenza after it hit several aged-care facilities hard in recent weeks - particularly in Sydney and Newcastle.
The Illawarra Shoalhaven public health unit has also recorded a rise in "influenza-related viruses" and is urging the community to be doubly careful about hygiene to avoid its spread.
Dr Alison Tomlin, of Shell Cove Family Health, said though the flu season was late, it was not too late to get vaccinated.
"Flu vaccines are available free to certain risk groups, including people with chronic health conditions like asthma, diabetes, obesity and heart disease," she said.
"We would particularly encourage pregnant women and the elderly, for whom the vaccine is also free, to get vaccinated.
"Apart from getting vaccinated, people also need to be mindful that if they are unwell they should stay at home and avoid contact with others, particularly those with impaired immunity.
"If they need to be out and about, they should use simple hygiene practices such as covering their mouth with a tissue when they sneeze or cough, as well as washing their hands or using hand sanitiser regularly," Dr Tomlin said.
Each year the influenza vaccine contained three different strains of influenza.
The 2014 vaccine contains two strains that protect against the influenza A strains called H1N1 and H3N2, and one strain that protects against the influenza B strain.
"Throughout July, flu notifications have been higher than previous months throughout the Illawarra and Shoalhaven," she said.
"More people are presenting to casualty and admissions to the region's hospital for flu and pneumonia are above average levels at present.
"Because the flu season has started later than usual, I would imagine the peak season would continue for another four to six weeks."
According to NSW Health, so far this winter all three strains of influenza in this year's vaccine have circulated. The dominant one is A H3N2, to which the elderly are especially susceptible.
Dr Vicky Sheppeard, director of NSW Health's Communicable Diseases Branch, said 24 aged-care facilities in NSW reported influenza outbreaks during July affecting 61 staff and 318 residents, 45 of whom had been taken to hospital.
"Almost 2800 cases of confirmed influenza were notified in July and we are also seeing high rates of flu activity in hospital emergency departments, especially in people over the age of 65."