About 500 people were waiting in line for a swine flu shot at the Olympic Oval on Wednesday morning. (CBC)

Hundreds of children, pregnant women and elderly people lined up for an H1N1 shot Wednesday inside the Olympic Oval, where the wait was as long as six hours.

The new clinic on the University of Calgary campus opened Wednesday morning after complaints about high-risk groups facing long lineups, often outdoors, at the four other clinics in Calgary. Those clinics are open to any Albertan over six months old who wants the vaccination against the strain of H1N1 influenza A virus causing the current swine flu pandemic.

Carla Abraham, who brought her two young children to the Olympic Oval, said the long line was daunting but not surprising.

"They have been promoting that everybody get the H1N1, so the fact that all these people showed up to get it shouldn't be a surprise," she said. "Four or five hours is not going to be pleasant. It's not going to be fun. But I am also not willing to risk my kids' health. I think it's really, really important we get the shot."

28,000 vaccinated in Calgary-area

Dr. Judy MacDonald, deputy medical officer of health, said Wednesday afternoon that she didn't know just how long people were waiting in line at any of the city's five clinics.

"I think it changes on probably a fairly regular basis," she said.

On the first two days of the province's mass vaccination campaign, 28,000 people in Calgary and the surrounding areas were vaccinated, she said. Another 9,000 health care workers in the region have also had shots.

A pregnant woman lines up for a swine flu shot at the busy Olympic Oval clinic. (CBC)

Emergency rooms and intensive care units are busier than usual, more schools are reporting absentee rates of more than 10 per cent, and the province's nurse-staffed phone line, Health Link, is experiencing lots of calls, she said.

"It's very, very busy and they may be overwhelmed," she said of Health Link. "Measures are being put in place to address that, but we also want the public to know there are many other ways to get information. There is great information, a great resource, on the Albert Health Services website."

Amy Frank, who is 30 weeks pregnant, and her two sons, went twice to other clinics since the vaccination campaign started Monday to try to get a shot but gave up when she saw the long lines.

"There was a three-hour wait outside," Frank said, waiting in the line at the Olympic Oval on Wednesday. "You can't really do that with two small kids."

The clinic caters only to pregnant women, children six months to 10 years old, seniors and family members accompanying those patients. It is also open to U of C students, faculty, staff and their families, but Alberta Health Services is asking these groups to wait until Friday before getting in line.

Officials have stopped giving the seasonal flu vaccine at all the Calgary clinics to focus on delivering the H1N1 shot. Community health centres in Calgary temporarily closed Tuesday so that the vaccination clinics can be fully staffed. They'll remain closed until further notice.

Schools report varying absentee rates

Many parents told CBC News they pulled their children out of school to wait in line for the shot.

Schools are required to contact public health authorities whenever the absentee rate climbs above 10 per cent.

"What we are seeing now, I've never seen before," said MacDonald. "We've been getting upwards of 10 reports like that from schools in the Calgary area for the last week or so, so we know there is a lot of influenza-like activity out there."

While the Calgary Board of Education won't reveal which schools have high absentee rates, spokesman Ted Flitton said some schools are reporting student absences of between one and 30 per cent. Besides children missing class to get flu shots, some students are sick and others may be looking after ill siblings, he said.

"If we do have a confirmed case, as far we can tell is confirmed, we aren't waiting around," Flitton said. "We are sending letters home. We have also been sending letters home saying kids are generally sick. They are displaying these sorts of symptoms and here is how you need to deal with your child."

Schools are sanitized every evening and health authorities will advise schools with high illness rates if any further measures are needed, he said. Closing schools is up to the provincial health and education departments.

Paramedics trained to administer vaccine

The province is hoping to get the vaccine to doctors' and 400 specially trained pharmacists as soon as possible.

Rick Fraser, who is the head of the union representing paramedics in Calgary, said paramedics will start training on how to administer the vaccine right away.

"I think what you'll see is paramedics starting to administer it to their own staff and staff that are on the front lines, and also being able to give it to the high-risk patients," he said. "Then other people who want it inside the flu clinics and other venues."