WINNIPEG — The country's chief public health officer says Canada is leading the world when it comes to the percentage of its citizens vaccinated against the swine flu.

Dr. David Butler-Jones says about 20 per cent of the population has received the H1N1 shot in the last three weeks. Canada has about 33 million people.

"That's just unheard of," he said in an interview while he was attending an international conference on HIV/AIDS in Winnipeg on Monday. "Already we've immunized more people than anybody else in the world as a percentage of our population."

Health Minister Leona Aglukkaq told the House of Commons some jurisdictions will have completed their vaccinations by the end of this week.

"We had said all along that we were trying to complete the vaccination program by December. In fact, we were early in the rollout of our campaign across the country," she said. "By the end of this week, we will have over 10.4 million vaccines in provinces and territories."

Up to 95 per cent of the people in some remote northern Manitoba reserves, which were given priority because they were hit particularly hard when swine flu first hit in April, had received shots as of last week.

At least 161 Canadians have died from the virus since it surfaced in the spring. But Butler-Jones said Canada hasn't suffered as much as other countries.

"Every death is tragic, but the fact that we've had as few deaths as we've had and as few serious cases is testimony to everybody working to address this disease," he said. "This is actually a model of success."

The vaccine rollout has come under serious criticism since immunization clinics opened across the country a few weeks ago. Although pregnant women were considered a top priority, the vaccine which was recommended for expectant mothers had to be shipped from Australia and took several weeks before it was available in Canada.

Other people waited hours in lengthy lineups at mass immunization clinics. Some -- such as Calgary Flames hockey players -- jumped the queue in Alberta and were given the shot privately. Many clinics across the country had to shut down entirely for days because of a national vaccine shortage.

Despite that shortfall, some vaccine has had to be thrown out because of its short shelf life. Officials with some of the larger health districts, including Toronto and Halifax, say they have tossed about one per cent of their vaccine because it had expired.

In Manitoba, a shipment of 1,000 doses was wasted after it was stored in a freezer instead of a refrigerator.

"It is a small percentage in the total," Butler-Jones said. "Obviously everyone wants to minimize that but, at the end of the day, we're fortunate in Canada that we will have sufficient vaccine for everybody."

Despite initial problems, Butler-Jones said vaccine shipments are now flowing well, which will mean even more people will be eligible to get the shot soon. There will be several million doses available this week and another three million doses are expected next week, he said.

"Very quickly, I think access will continue to improve. We're still on target that by the end of the year, hopefully before Christmas, anybody who wishes to be immunized will be."

A more expanded campaign is already in the works in Alberta, where the government announced Monday it is easing restrictions on who gets a shot. The vaccinations will be given next to all seniors over 75, as well as to their spouses or partners. Starting Thursday, anyone between 65 and 75 will be eligible.

The general public is expected to follow later this week or next.

Health Minister Ron Liepert said the vaccine supply has improved to the point that shots no longer have to be limited to high-risk groups.

But federal Liberal health critic Carolyn Bennett contends that there will be people across the country who will have to wait until the new year to get a shot -- too late to escape the peak of the virus expected in December. Some 35 other countries beat Canada to the punch in ordering the vaccine for the second wave of the pandemic, she said.