* Officials turn people away as lines lengthen
* Two well-publicized deaths fuel public concern (Adds statement from Health Canada)
TORONTO Oct 29 Canadian officials warned on Thursday that vaccines for the H1N1 virus would likely be in short supply, as thousands of people across the country lined up to get swine flu shots.
Within about half an hour of clinics opening for high-risk patients in Toronto, officials started turning people away and warning those in line that they might have to wait six or seven hours.
Later in the day, Health Canada said vaccine supplies would get even tighter next week.
Shipments to the provinces and territories would slow because the supplier, GlaxoSmithKline (GSK.L), had temporarily shifted production to a type of vaccine recommended for pregnant women, the federal government agency said in a statement.
That will reduce supplies of a more powerful version suitable for the general population next week, the ministry said, although the flow is expected to pick up afterward.
"We continue to work with both GSK and provinces and territories to ensure all Canadians who want to be vaccinated will be immunized by Christmas," it said.
The statement came after the western province of Manitoba said the federal government had warned the provinces that "significantly less vaccine" than expected would be delivered.
"Regional health authorities may have to adjust their clinic schedules, including postponing clinic dates, until there is sufficient vaccine supply," health authorities in Manitoba said.
In Toronto, Canada's largest city, public health spokeswoman Rishma Govani said public sentiment on the H1N1 virus had swung from complacency to concern after news a teenager and a young girl had died from the H1N1 virus.
"The whole outlook changed within days and escalated and expanded," Govani said, noting Toronto had moved up its plans for opening clinics to the public by several days.
"People just got scared or panicked."
She said the city's public health officials wanted people to get vaccinated when possible, but the effect of swine flu was usually mild unless there were pre-existing medical conditions.
Two high-profile cases in the province of Ontario rang alarm bells with the public. A 10-year-old girl with no previous medical problems died from the flu in eastern Ontario and a teenage hockey player died in Toronto.
"The medical experts are emphasizing that those examples are exceptions," Govani said.
At the East York Civic Centre in Toronto's east end, Meegan Loudon had already waited four hours with two children, aged 4 and 7, and she was still far from the front of the line.
"The feeling isn't one of overwhelming frustration," Loudon said. "It feels like everyone here is trying to do the best they can."
The Canadian government has ordered enough vaccines for everyone in Canada, which has a population of more than 33 million. Vaccinations began this week for children, the elderly and other high-risk groups, with clinics ramping up in increasing numbers next week. (Reporting by Randall Palmer and Jeffrey Hodgson in Toronto; Editing by Peter Cooney)