After a record number of flu cases last year in Australia, experts are warning all Australians of the need to get the latest updated annual vaccine - as well as adopt other hygiene measures to reduce their risk. So far this year, 63,000 cases of influenza have been recorded nationally, and experts say it's already a relatively high number for this time of year - the start of the flu season. But whether this year will be a severe flu season depends on a number of factors.