"It can be very unpredictable. You start to see a surge once the colder months settle in.
"We probably prevent the cases where it's become a crisis and an ambulance is needed ... people waiting until they're in absolute dire straits and they're having to ring for an ambulance.
"The big message for us is deal to your symptoms early and don't wait until you're in a crisis."
St John's advice was to treat minor symptoms at home such as common colds and sore throats, but if they persist the doctor should be called.
Yanko said neighbours and family members should be aware of those who were vulnerable like the elderly and very young.
He encouraged anyone who hadn't already got the flu jab to do so as it wasn't too late, with the peak of the flu season often coming in the middle and end of winter.
The Whanganui District Health Board said flu season had not yet started and only a few cases of flu-like illness had been seen at the Emergency Department.
The DHB promoted April as the best time to get a vaccination before winter.
People can get the flu jab from their GP, nurse or qualified vaccinating pharmacist and it is free for the more vulnerable groups such as over 65s and pregnant women.
Some employers provide their staff with free immunisation otherwise they are available for a fee.
This year's vaccine was expected to offer protection against the strain circulating in northern hemisphere countries.
The vaccines contained four inactivated virus strains, specially formulated for thus year's virus season.
There were no live viruses in the vaccine, which meant people could not catch the flu from the vaccine.
