One million Albertans have been vaccinated for H1N1, Alberta Health Services said Friday, but more than two million have not. (CBC)

Alberta Health Services has given more than one million people the H1N1 vaccine in the six weeks since the program began, the agency announced Friday.

Calling it "a tremendous accomplishment," Dr. Gerry Predy, senior medical officer of health, noted that earlier flu campaigns typically provided vaccine to 600,000 people over a six-month period.

Predy also called on the more than two million Albertans who have not been vaccinated to do so.

Vaccination clinics are still in operation around the province, and the H1N1 vaccine is now being made available to family physicians and other groups, Alberta Health Services said in a release.

Last month, health officials expressed concern about complacency over the vaccination, when lineups at H1N1 clinics dwindled once the vaccine became widely available. They warn of a third wave of the flu expected to hit in February or March.

"So if you have a lot of people that are still susceptible to this flu, you can expect that you're going to see a lot of people ending up in hospital or in the intensive care unit," said Dr. Glen Armstrong, head of the microbiology and infectious diseases department at the University of Calgary.

Health officials said they will be shifting the operating hours of some clinics in Calgary, starting on Sunday. The public should check the Alberta Health Services website for the most up-to-date information.