Five people in Alberta — including a child — have died from influenza so far this season, and Alberta Health Services says there has been a "significant" increase in week-over-week reported hospitalizations.

Two people died in the Calgary area, and three deaths were reported in the Edmonton area.

AHS Senior Medical Officer of Health Dr. Gerry Predy, left, and Dr. Martin Lavoie,Acting Chief Medical Officer of Health, provided an update Thursday on the five flu-related deaths in Alberta this week. (Gareth Hampshire/CBC) Four of the five who died from lab-confirmed influenza had not been immunized, and the child who died had received one of two doses of the vaccine necessary for children under nine years of age who are being immunized for the first time.

"It's not unexpected," AHS senior medical officer of health Dr. Gerry Predy said Thursday. "Influenza, when it does hit, it does cause severe illness and unfortunately in some cases, death.

"In the last week, we've seen a number of hospitalized patients increased from 30 previously to 84, so that's more than doubling in the course of a week.

"One Albertan death is too many, and this week we have the unfortunate responsibility of confirming five. If that isn't enough to encourage immunization, the upswing in hospitalizations is yet further evidence of the very real severity of influenza."

Two of the five people who died from influenza were 65 or older. Two were under 18, and one was between 18 and 64. Three of the five died from the H1N1 strain of influenza.

More than two million doses of influenza vaccine were purchased for use in Alberta this season. Since Wednesday, slightly more than one million of these doses had been used.

The vaccine can't be used for children younger than six months. It is available for free to all Albertans over that age.

Whether you're healthy or not, you get direct protection from the vaccine and its the best way to protect yourself. - Dr. Martin Lavoie

Predy said although this year's flu season started later than last year, it's still in the early stages and it's not too late to get vaccinated.

"The influenza season ... comes from the end of October to the end of April," Predy said. "But in that season, we get spikes and activity, what we call annual outbreaks, and this is the start of an annual outbreak. It happens every year. It's not unusual."

This year's dominant strain is H1N1, Predy said. The strain tends to affect adults, children and infants more often and more severely than the H3N2, he said, which can affect the elderly more severely.

The vaccine protects against both, said Dr. Martin Lavoie, acting chief medical officer of health.

"It's very important to remember that when influenza is around we have a number of most vulnerable people out there," Lavoie said.

"Whether you're healthy or not, you get direct protection from the vaccine and it's the best way to protect yourself. When you do that, you protect others around you by preventing the spread of the virus to other people who would be vulnerable."