TORONTO - Canadians who chose not to be immunized against H1N1 during the pandemic will have another shot at getting protected with this year's seasonal flu vaccination.
Next week, provinces and territories across the country will begin rolling out the 2010-11 vaccine, which includes H1N1 A and two other strains -- H3N2 influenza A Perth and influenza B Brisbane.
All children over six months old and adults of all ages are encouraged to get a flu shot, said Dr. Patricia Huston, senior medical adviser for the Public Health Agency of Canada.
"It will protect you against the pandemic H1N1 strain, for example," said Huston. "But we anticipate it will be a new H3N2 strain that will be circulating this year, so previous flu vaccines will not cover you for that."
"Even if you've had the H1N1 vaccine, so you say: 'Why should I get it again?' ... there is no harm in having a repeat vaccine or a booster, and it will protect you for the new strains that may be coming out."
A recent Statistics Canada survey found only about four in 10 Canadians aged 12 and older -- or about 11.6 million people -- rolled up their sleeves for an H1N1 shot last season. The vast majority of those who didn't get inoculated said they thought it unnecessary, despite public-health warnings and widespread media reports about the pandemic.
For this season, the Public Health Agency has ordered 11.2 million doses of the trivalent vaccine from manufacturers GlaxoSmithKline and Sanofi Pasteur, based on requests from the provinces and territories. Total cost of the bulk order: about $40 million to $45 million.
Provinces and territories began shipping vaccine last month to their health units, and distribution to clinics, long-term care facilities and doctors offices is already underway.
The mid-October rollout of the vaccine allows for a pre-emptive strike against the flu, which generally begins circulating in earnest in December and continues making Canadians' lives miserable through February and often into March.
"Once you have flu vaccine, it takes a couple of weeks for your antibodies to form so you have full protection," said Huston. "So by getting things out by the middle of October, this still leaves six weeks ... for people to get vaccinated well before the flu season starts."
While this year's vaccine won't be offered on a priority basis to high-risk groups, as it was during the H1N1 pandemic, public health officials are stressing that people vulnerable to complications should get their shots as soon as possible.
Most people recover in about a week from the runny nose, nasty cough and aching muscles caused by the flu. But for others, the disease is nothing to sneeze at. Influenza can weaken the body's ability to fight off other infections, such as pneumonia, and can even be fatal. At least 4,000 Canadians die from flu-related complications each year.
The National Advisory Committee on Immunization, or NACI, has lengthened its list of those considered at high risk for complications from influenza -- including the elderly, young children and people with underlying health conditions. Close contacts of high-risk groups and health-care and essential-service providers are also urged to bare their arms for a shot.
This year, NACI has added three other groups it considers at elevated risk for complications: those who are morbidly obese, with a BMI of 40 or higher; aboriginal people, who were found to be more susceptible during the H1N1 pandemic; and healthy children aged two to four.
As to how the post-pandemic flu season might shape up, that's anyone's guess, say experts.
"We're obviously watching very carefully as to what's going to happen," said Dr. John Spika, director general of PHAC's Centre for Immunization and Respiratory Infectious Diseases.
With more than 40 per cent of Canadians inoculated against H1N1 last season -- plus those who have immunity through direct exposure to the virus -- "it's possible that we may have fair levels of protection still within the population," Spika said, noting that studies are underway to determine how long immunity lasts among those who were vaccinated.
"So the likelihood that H1N1 may come back and pick up the remaining susceptibles, it's always there."
Dr. David Williams, Ontario's associate chief medical officer of health, agreed that "predicting the flu season is worse than predicting the weather."
But the province's theme for this flu season is "getting back to business" after the pandemic, he said.
Ontario has purchased five million doses from PHAC, and all residents are eligible for a free flu shot under the province's universal influenza immunization program.
Health units will start inoculations through public clinics next week, and staff at long-term care facilities will begin immunizing residents. Some doctors' offices may also have the vaccine ready to go for patients.
Williams said that virus tracking in the Southern Hemisphere, where the flu season is ending, has shown that the H3N2 strain has been the most predominant.
There has also been some early influenza activity in Canada. In southern Ontario, for instance, two long-term care residences and one school had recent outbreaks of H3N2.
"We're looking to see if they are travel-related. It's hard to say for sure," said Williams. "But it shows that we do have H3 circulating ... and we're pleased that so far this year it's a match with (the vaccine)."
The U.S. Centers for Disease Control released a report Thursday showing there have been low levels of flu in the United States throughout the summer as well as typical seasonal influenza activity in the Southern Hemisphere.
"The vast majority of the viruses that have been analyzed recently are like the viruses included in this year's vaccine," the CDC said.
While it may be six weeks or so before the country gets slammed by the annual onslaught of flu, some Canadians are already battling nasty sniffles and hacking coughs and may be wondering if it's influenza.
Probably not, said Williams.
"We have lots of other viruses moving -- a lot of rhinovirus and adenovirus, too. So none of the other viruses are taking a holiday. They're coming back with their usual interest in the fall."
