The latest numbers from Alberta Health Services show Calgary accounts for more than half of all the influenza cases in the province.

There have been 652 lab-confirmed cases of influenza in Calgary since the end of August, and 190 people have been hospitalized because of the virus. 

"That's more than half of the total that Alberta has," said Calgary's medical officer of health, Dr. Judy MacDonald.

"And that's not unexpected because we know influenza is serious and can result in the need for hospitalization."

The vast majority of cases are influenza A, H3N2, which is the predominant strain. It tends to hit older people and children under two the hardest, MacDonald said.

Provincewide, there have been 1,147 cases of flu confirmed, with 320 Albertans admitted to hospital.

In Calgary, there have been 505 cases of influenza A, and 147 cases of influenza B. In Edmonton, there have been 115 cases of strain A and nine cases of the B strain.

There have been five deaths related to the flu so far this season in Alberta — three in the Calgary zone, one in the south zone and one in the Edmonton zone, AHS says.

Craig Jenne, who teaches microbiology at the University of Calgary, says scientists were predicting a bad flu season in Alberta after Australia experienced higher hospitalization and death rates during its flu season.

"A flu season is several months long and if what we're seeing is most of the infections now, followed by very few to no infections in January and February, this is going to work out to be an average flu year," he said.

"So it's really hard to say this early on. If these numbers sustain throughout the flu season, then, yeah, we're looking at, unfortunately, a very nasty flu season."

Efforts to persuade Albertans to get vaccinated seem to be paying off, with the number of people who have received the flu shot this year up by 100,000 over the same time last year, AHS says.