Health Canada has approved the H1N1 vaccine, meaning the first Canadians to take part in the country's largest-ever immunization campaign could get their shots as early as the end of the week.

"I am happy to say that today, Health Canada has authorized the H1N1 flu virus vaccine," Health Minister Leona Aqlukkaq announced to reporters Wednesday.

"This means the adjuvanted vaccine has been judged safe and effective for use in Canada by the manufacturer, GlaxoSmithKline, as well as by Health Canada regulators," she said.

"I encourage all Canadians to get vaccinated, since there is simply no better way of fighting the H1N1 virus."

Two million doses of the vaccine have already been shipped to the provinces and territories, who will administer vaccination programs through flu clinics offered by local health units.

GlaxoSmithKline hopes to ship around 3 million doses a week to the provinces.

Aglukkaq reiterated that all Canadians can access the vaccine, since the federal government has ordered 50.4 million doses.

Another 1.8 million doses of the vaccine without an adjuvant, a compound that boosts immune system response, are also on the way. But the timing of when that will be available remains unclear; the unadjuvanted vaccine is being manufactured, packaged and shipped separately.

Dr. David Butler-Jones, Canada's chief public health officer, encouraged all Canadians to get the vaccine, if not to protect themselves, then to protect those around them.

"Frankly, I don't want to be the cause of someone's serious illness of death," he said noting that recent data suggest that those under 25 are at highest risk of serious illness from this new virus.

He added that any side effect risks from the vaccine are remote.

"Serious adverse events following immunization are rare. For the seasonal flu shot, the rate of reported serious events is about one in every million people immunized. The benefits of immunization - the prevention of serious illness and death - far outweigh any theoretical risks," he said.

Conflicted views on vaccine

Despite the recommendation of Canada's top doctor to get the vaccine, the majority of Canadians say they won't get the shot according to a recent poll.

The Canadian Press Harris-Decima poll in early October said only a third of Canadians said they would get the vaccine. In the same poll, two thirds of Canadians said they were not concerned or very little concerned about the H1N1 virus.

Aqlukkaq admitted on Â鶹ӰÊÓ Channel's Power Play that promoting the vaccine and the surrounding health issues has been difficult.

"The biggest challenge has been to communicate based on the science," she said.

The health minister recommended Canada's talk to their family physician if they have questions about whether to get the vaccine, or visiting the government's website.

However, even some doctors are conflicted on how to promote the vaccine, due to the relative lack of data.

"I think many physicians in a position to promote the vaccine are having hesitation because they feel they don't have enough safety data to stand on the table to say everybody must do this right now," Dr. Neil Rau told Â鶹ӰÊÓ.

But Aqlukkaq said she is planning to get the shot and every Canadian should do so as well.

"Every Canadian should know that Health Canada . . . has stated time and time again that no step will be skipped to ensure the vaccine for Canadians will be safe and effective," she added.

Safety, effectiveness data from European studies

Canadian clinical trials of the vaccine are still underway, and the results won't be available until next year. So federal health authorities have relied on data from clinical trials done on the same vaccine in Europe. Those trials have found the vaccine safe and effective; the vaccine produces antibodies in over 90 per cent of adults aged 18 to 64.

The adjuvant used in Canada's swine flu vaccine, AS03, has also been tested in about 45,000 people around the world using a "mock" H5N1 vaccine. No significant safety concerns were detected, Health Canada reports. Canada has never approved a flu vaccine containing an adjuvant before.

The Canadian clinical trials are expected to add to the safety and effectiveness data, by focusing on the vaccine's effects in select population groups, such as First Nations, people who are HIV-positive, children and pregnant women.

Because some reactions from vaccines are so rare they arise in only one in a million cases, the final picture of the vaccine's safety won't be clear until after the immunization program is underway, Health Canada has acknowledged.

Dr. Butler-Jones said adults will need one dose of swine flu vaccine, but children under the age of 10 will need two, just as they do with seasonal flu shots. The vaccine is not intended for infants younger than six months.

And while pregnant women are encouraged to receive the vaccine without the adjuvant, if the unadjuvanted vaccine is delayed, they should get the regular swine flu shot to protect themselves and their babies, since pregnant women are at much higher risk of complications from the flu.

About 4,700 people worldwide have died of H1N1 to date, including 83 deaths in Canada. Another 300 or so Canadians have required care in intensive care in hospital.

The Public Health Agency of Canada says everyone aged six months and older should get the vaccine, but those who will benefit most, and those who care for them, include:

  • People under 65 with chronic health conditions. (These include: heart disease, diabetes, asthma lung disease, kidney disease, liver disease and severe obesity.)
  • Pregnant women
  • Children aged six months to less than five years
  • People in remote and isolated communities
  • Health care workers involved in the delivery of essential health care services
  • Household contacts and care providers of persons at high risk who cannot be immunized

Anyone over the age of 10 should receive one dose of adjuvanted vaccine. Children between six months and 10 years of age should receive the adjuvanted vaccine in two half-doses, administered at least 21 days apart. The vaccine is not recommended for children under the age of six months.