Winnipeg's 12 H1N1 clincs experienced long lineups on Friday, as health officials expressed concern about the supply of vaccine. (CBC)

Lineups at H1N1 clinics in Winnipeg started forming early Monday morning on what health officials say could be the last day of mass vaccination clinics.

More than 200 people were already waiting at the River Heights clinic inside the Grant Park Shopping Centre at 8 a.m., even though the clinics didn't open until 9:30 a.m. The first people in line told CBC News they arrived at 6 a.m.

By the time the clinic opened, there were about 500 in line.

On Friday, the provincial government announced the clinics in Manitoba, which started last week and were originally scheduled to continue this week, would be scaled back due to a shortage of the vaccine.

Staff at H1N1 vaccination clincs in Winnipeg will be closely screening people on Monday to make sure they fall into one of the priority groups. (CBC)

Manitoba Health Minister Theresa Oswald told CBC News on Friday that Manitoba would be getting less than one-quarter of the number of the swine flu vaccine doses that officials were expecting.

She said the province was supposed to receive 72,000 doses this week, but that had been reduced to 15,500. It is up to individual health regions to decide which clinics to postpone.

The Winnipeg Regional Health Authority (WRHA) then promptly announced it would be stricter on Monday about who gets the shot.

Up to now, the WRHA had urged people to abide by the list of priority groups set by the province. Because of the anticipated high demand for the vaccine, the government announced a list of those at highest risk for serious illness and asked that they get vaccinated first.

But no one at the clinics screened individuals to ensure they fell into one of the priority groups.

As last week progressed, and concerns were raised by health officials about a possible shortage of vaccination, more people who were not part of the priority lists filed into the clinics out of fear they might not get the shot otherwise.

Waits exceed 3 hours

The wait at some clinics in Winnipeg last week exceeded three hours. Often, the WRHA was forced to turn people away hours before the clinics closed because they were already at full capacity.

By the end of Friday's clinics, 65,050 people had been vaccinated in Winnipeg alone.

For Monday's clincs, the WRHA has narrowed its priority list from 10 key categories to just four, and has promised to screen people to check if they fall into one of the following groups:

• Children aged six months to five years old.
• Anyone of aboriginal ancestry, including First Nations, Métis or Inuit.
• People under age 55 who have a severe chronic medical condition or another risk condition.
• Pregnant women.

The health region said those groups will likely exhaust its supply of vaccine by the end of Monday. If not, the clinics will stay open only as long as current supplies last.

The province is still expecting to receive batches of the vaccine throughout the next few weeks, but the amount it will get has yet to be determined.

'We really need to focus the vaccine right now for the people who are most at risk for serious illness.'—Dr. Sande Harlos, WRHA medical officer of health

Even so, health officials are still promising that everyone who wants the vaccine will eventually be able to get it.

"We do want to remind people that there will be enough vaccine for everybody. It's great that we do have quite a large proportion of Winnipeg …10 per cent [of the population] within a week already immunized, but we really need to focus the vaccine right now for the people who are most at risk for serious illness," said Dr. Sande Harlos, WRHA medical officer of health.

People not in the high-priority categories will be asked to come back when stocks of the vaccine are replenished, she said.

"If people [not considered high priority] do come, we really want to try and greet them early, explain the situation if they haven't already heard about that, and make sure they don't spend time waiting in a lineup when it's not going to result in them being immunized," Harlos added.

The WRHA will evaluate how much vaccine they have before they announce when the clinics will reopen beyond Monday.