Prairie provinces are ramping up operations against the H1N1 virus, with Manitoba now extending its vaccine priority list to include anyone 18 years old or younger, and Alberta requesting more ventilators from the federal government.

Dr. Joel Kettner, Manitoba's chief medical officer of health, said there are signs the virus is peaking among youth.

"We've got some indicators from schools that absenteeism has been rising," he told reporters on Wednesday. "And we are also aware that children are one of the most important sources of spread of viruses, particularly influenza viruses, within the community."

Meanwhile, it appears that at least one province is taking advantage of a stockpile of ventilators amassed by the Public Health Agency of Canada in the event of a flu pandemic.

The Canadian Medical Association Journal reports that Alberta received this week 45 ventilators from the stockpile. They will be sent across the province to increase the capacity to treat patients in critical care units.

The province bought about 100 ventilators earlier this month, and now Alberta Health Services' Senior Medical Officer of Health Dr. Gerald Predy says they have dipped into the federal stockpile as well.

Predy said intensive care units in Alberta's hospitals are currently managing with the number of people ill with H1N1 influenza in hospital, but that more patients are expected to need care in the next few weeks.

"We anticipate, from what we are seeing (now), that we are going to see more critically ill people with H1N1 over the next couple of weeks, for sure, so we just want to be as prepared as we can," Predy told the CMAJ.

About 100 people with confirmed or suspected cases of flu are receiving care in critical care beds, which is about one-third of the available ICU beds in the province.

Since April when H1N1 first emerged in Canada, there have been 29 confirmed H1N1-related deaths in Alberta, and about 615 confirmed hospitalized cases.

Predy said Alberta is also reviewing public health programs across the province to see what it can suspend in order to redeploy staff to critical care areas. It has also developed a short refresher program for nurses who may have once worked in ICUs but have not done so recently.

Ontario also recently bought about 216 new ventilators in anticipation of a surge in seriously ill H1N1 patients. The province expects to distribute the additional ventilators to teaching hospitals this month.

A number of hospitals in northern Ontario have exceeded critical care capacity while some in Toronto have delayed some elective surgeries because of a lack of capacity in critical care units.