Influenza cases in South Australia have doubled this year with elderly people among the worst affected.
Some 1,519 cases of influenza have been recorded so far, compared with about 700 at the same time in 2014.
Outbreaks have been reported at 15 aged care facilities, with a delay in flu vaccine production blamed as a potential culprit behind the spike.
Chief medical officer Paddy Philips said production delays were caused by the need to add two new strains to the vaccine this year.
“The flu vaccine arrived a bit later than normal in March and April and, possibly because that’s led to some delays, it’s led to an early start to the flu season,” he said.
People aged 65 and over accounted for more than 37 per cent of the cases reported so far.
State Health Minister Jack Snelling said there may be more cases because it was not mandatory to report them.
“The flu season seems to be hitting very early this year, which is always ominous,” he said.
“It concerns me a great deal about our emergency departments going into the winter season.”
SA Health said it had plans for separate flu clinics within public hospitals should the spread of influenza worsen over winter.