TORONTO - Leaves are turning, days are shortening — the classic signs that winter is on its way. With winter comes cold and flu season, so with autumn comes flu shots.

Provinces and territories have launched or are gearing up for the annual effort to persuade Canadians to vaccinate themselves and their children against influenza. Though many jurisdictions now give the vaccine for free to all comers, it is believed fewer than one-third of Canadians take flu vaccine and in some places the number may be more like one in four or one in five.

"That's an ongoing challenge," admits Dr. Jeff Kwong, a public health physician at Toronto Western Hospital who has done a lot of research on flu vaccine issues as a scientist at the Institute for Clinical Evaluative Sciences, also in Toronto.

"I think if governments want to keep higher uptake they really need to invest in promotion."

There still are some provinces — Prince Edward Island and British Columbia, for instance — that only pay for vaccine for people deemed to be at high risk from the complications of flu.

High risk people typically include seniors, children between the ages of six months (the earliest point at which flu vaccine is given) and five years, pregnant women, and children and people with certain health conditions. Some also covered are people who care for these high-risk individuals and could transmit flu to them, though the list differs from province to province and people in doubt should check their health ministry's website or ask a doctor.

Kwong, who has studied Ontario's universal flu shot program — which was the first in the world when introduced in 2000 — says it doesn't matter so much whether a program is free for all or only for targeted groups, so long was people are vaccinated.

"So it's not just good enough to offer it for free to everyone. You actually have to find a way to get them into people's arms," he says.

Dr. Barbara Raymond, director of pandemic preparedness at the Public Health Agency of Canada, says this year provinces and territories have jointly purchased about 10 million doses of vaccine from four suppliers: GlaxoSmithKline, Sanofi Pasteur, Novartis and AstraZeneca. The first three make injectable vaccine while the latter sells Flumist, an aerosol that is sprayed into nostrils. It is licensed for use in children and adults between the ages of two and 59.

The vaccine available in a particular province or territory depends on what that jurisdiction ordered. So while some are offering Flumist for children, or are using Fluad, an extra strength vaccine for seniors made by Novartis, others may not.

But even if a particular type of vaccine isn't covered by the provincial or territorial campaign, it's possible a person could get that product from a physician, if they are willing to pay out of pocket.

Where a decade ago there were only two licensed suppliers of flu vaccine in Canada, now there are eight authorized vaccines, says Raymond. More are on the way, including vaccines that protect against four strains of flu — two influenza As and two influenza Bs. All vaccines used this season in Canada will be trivalent, protecting against two As and a single strain of B.

Divvying up the market works as a hedge in case any single manufacturer has a product line failure, as has happened in the past. And keeping more companies in the business of making flu vaccine is also part of efforts by a variety of governments to have maximum production capacity available for when rare flu pandemics occur.

But buying a mix of products creates organizational challenges that were not a concern when everyone who walked into a flu shot clinic got the same serum. Now planners have to try to have enough of each type in the right places, so that vaccines like Fluad that are used in a targeted group actually get offered to the people who need them.

"It does increase the organizational complexity," admits Dr. Perry Kendall, British Columbia's chief medical officer of health. "So it really does depend on good projections and good planning."

Raymond acknowledges the challenges on the planning side, but says the hope is that using a variety of vaccines will result in better protection. "It's a lot more complicated from the program and planning point of view, but hopefully from the effectiveness and the uptake point of view we're better addressing the needs of the population rather than the needs of the people who are trying to put programs into place."

Some provinces have already started administering flu vaccine. New Brunswick launched its campaign this week. In Ontario, vaccine is starting to roll out to doctors' offices and other locations now. And in Yukon, clinics in Whitehorse are already completed. Other provinces will be starting in the next few weeks.

In some jurisdictions, vaccine is available through doctors' offices and public health clinics. And in some, pharmacists have been brought into the mix. Ontario, British Columbia and Nova Scotia are among the provinces that allow pharmacists to give flu vaccine.

In British Columbia, the campaign won't begin until early November, says Kendall. That's because regional health authorities there wait, for organizational ease, until they have 90 per cent of their vaccine deliveries in hand "rather than dealing it out in dribs and drabs."

In Manitoba, Dr. Tim Hilderman says doctors have already started administering vaccine, but the lion's share of the work will be done in public clinics that will start the week after Thanksgiving.

Says Hilderman: "If we could do the bulk of our immunizing in the first couple of weeks of the program — so the last two weeks of October and the first two weeks of November — we would be very happy. And that's typically how it ends up."

News from © The Canadian Press, 2013