Canadian health officials have until the end of the week to order the country’s stock of Influenza A (H1N1), also known as swine flu, vaccine needed for the upcoming fall flu season.

“We will be acquiring enough vaccine for those who we anticipate will want and need it,” Dr. Arlene King, Ontario’s medical officer of health, told a Toronto news conference yesterday.

“This is not an easy decision in light of the fact that risk groups are still emerging.”

Health officials believe Canada will obtain enough vaccine for its citizens from its domestic manufacturer, but King cautioned the country may face a shortfall at the beginning of the flu season.

“We’re not going to have all of the vaccine at all of the same time when we want and need it,” King said, noting GlaxoSmith­Kline, which has its production plant in Ste.-Foy, Que., has said its first supply of vaccine will likely be ready in mid-November.

Officials are currently working on a pandemic prioritization list that will set out which groups of Canadians will receive the vaccine first, and which King said will be ready in the fall. King held a special meeting in Toronto yesterday with the province’s 36 regional medical officers of health to discuss influenza preparations for the fall.