The pandemic H1N1 influenza virus in Canada is not as severe as expected nor is it spreading quickly, the country's top public health official has determined as he put the brakes on an early rollout of the vaccine.
Canadians will be able to get the swine flu vaccination in early November, which will allow Health Canada to review more clinical-trial data and follow the regulatory process it set out for approving the pandemic vaccine.
The United States, China and Australia have begun inoculating their citizens against swine flu, now the dominant influenza strain. But David Butler-Jones, Canada's chief public-health officer, assured Canadians yesterday that the majority of cases so far have been mild and, despite a few clusters in British Columbia, there is no widespread illness.
"Right now in Canada, unlike in the United States, we are not seeing widespread influenza activity," Dr. Butler-Jones said in a conference call. "We're many weeks behind the Americans in terms of rates of disease."
Canadian health authorities planned to push through bureaucratic red tape and move up the delivery of the vaccine if the disease turned more severe this fall. Despite assurances from Dr. Butler-Jones that this is not happening, some health experts fear that the virus could resurface with a vengeance this month, well before Canadians are vaccinated.
"We're definitely seeing an up-tick in flu cases," said Michael Gardam, director of infectious diseases prevention and control for the Ontario Agency for Health Protection and Promotion. "In my mind there's always been a real possibility that we could have a lot of this go by before we have the vaccine available."
Canada has ordered 50 million doses from GlaxoSmithKline, which is contracted to produce pandemic flu vaccine for all Canadians at its Ste-Foy, Que., plant. While other countries are rolling out non-adjuvant vaccine, Canada has decided to fortify its vaccine with adjuvants, which are chemical boosters that can increase production. Adjuvants are in many common vaccines in Canada, but have not previously been approved for influenza vaccines.
The H1N1 vaccine could potentially be approved by Health Canada based on a single clinical trial done in Germany on 130 healthy adults. That trial showed one dose, not two, is enough to provide immunity. Canadian trials are expected to begin later this month and results won't arrive until the end of next month or early December, well after the vaccine is rolled out.
Drugs - including vaccines - are routinely approved in Canada without domestic clinical trials. And health officials say components of the H1N1 vaccine have been proven to be safe: The adjuvant has been tested on thousands with the H5N1 avian flu drug, and the antigen has been tested in other trials in the U.S. and elsewhere.
Dr. Butler-Jones said the trials in Canada are being done to see if more than one dose will be needed to provide immunity to certain groups, and surveillance studies will be conducted after the vaccine is released. But, he said, "waiting for that data, and whether you need a second dose, is no reason to delay making sure you have the first dose and provide as much immunity as possible."
If the virus were to infect more people during the normal flu season, the vaccine would be available to prevent its spread.
Kumanan Wilson, Canada Research Chair in public health policy at the University of Ottawa, worries that there has been so much confusion about the vaccine that people will question whether they even want it. Not only have public-health authorities kept changing the timeline of when the vaccine would be rolled out, but also the use of an unfamiliar adjuvant has made many all the more skeptical, he said.
"Even if you get this vaccine out in November, it's quite possible that there may not be a huge appetite for it," Dr. Wilson said. He added: "But things can change if the virus gets really bad."