Ontario delays fall flu shots over H1N1 threat

Ontario has become the first province to delay seasonal influenza vaccines to most residents because of the threat posed by swine flu.

The decision, announced Thursday, comes as public health officials across the country are reconsidering their immunization plans in light of unpublished Canadian studies that suggest earlier seasonal flu shots raise the risk of contracting the pandemic H1N1 flu virus.

“Is it typical that we adjust our programs?” said Arlene King, Ontario's chief medical officer of health. “No, it isn't typical, but we are not dealing with a typical flu season this year.”

Ontario's program is based on a calculation that swine flu will sicken more people than seasonal influenza this fall and winter. Despite hopes for a pan-Canadian vaccination strategy, the province's approach is different than those in other provinces.

Alberta, Saskatchewan, Manitoba and New Brunswick are planning to widely offer seasonal flu shots next month, before swine flu vaccines, expected in November, become available.

“We are going to try to do it very fast and then focus on H1N1,” said John Tuckwell, an Alberta Health spokesman.

In New Brunswick, the seasonal flu vaccine is already being sent to doctors and should arrive in the next week. Once supplies run out, no more will be produced as the focus shifts to preventing swine flu.

“We want to avoid having both vaccines circulating at the same time in total confusion at the level of the public,” said Dr. Paul Van Buynder, New Brunswick's deputy chief medical officer of health.

Other provinces, including British Columbia and Quebec, have not yet decided how to roll out their vaccination campaigns.

“We have all the scenarios on the table,” said Karine White, a spokeswoman for the Quebec Health Ministry. “Right now, it seems like H1N1 is the major flu virus.”

The provinces' plans come amid signs that the flu season has started several weeks before a swine flu vaccine is ready. Hundreds of students in B.C. were absent from school this week, either because they are sick or their parents want to protect them from falling ill. The H1N1 virus has been confirmed in students in two Vancouver schools and one on Vancouver Island, and test results from a fourth school are expected as early as Friday.

Ontario's plan involves three waves of vaccinations. Seasonal flu shots will be offered starting next month to people aged 65 and older and to residents of long-term-care homes, who have largely been spared by swine flu. Once available, H1N1 vaccines will be provided to at-risk groups, including young children, pregnant women and people with chronic health problems, followed by the general population. Finally, seasonal flu shots will be offered to all Ontarians in December or January.

The approach is borne out of several considerations, including the epidemiology of the H1N1 virus and the unpublished research from B.C., Ontario and Quebec that appears to suggest that people who received a flu shot last year are about twice as likely to contract swine flu. The studies are undergoing fast-tracked peer review. Researchers in the United States, Britain and Australia have not found the same link.

In addition, immunity to both seasonal and swine influenza will require up to three separate vaccinations. Ongoing clinical trials are determining whether H1N1 immunity can be achieved in one or two doses.

Allison McGeer, an infectious diseases expert at Toronto's Mount Sinai Hospital, said Ontario's compromise makes sense.

“It's a reasonable balance,” she said. “[But] it has some obvious logistical challenges.”

With reports from Caroline Alphonso in Toronto, Katherine O'Neill in Edmonton, Patrick White in Winnipeg, Oliver Moore in Halifax and The Canadian Press


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