TORONTO -- Summer is starting to seem like a distant memory. And the remains of your Thanksgiving turkey may not yet be boiling for soup stock.

Still, public health officials are hoping you will soon turn your thoughts to preparing for flu season.

As temperatures drop, the viruses that make people sick during what we call flu season start to circulate. Flu season isn't like hunting season. There is no fixed date for its start; it begins when people start getting sick.

And there are signs that this year that wave of illness could start early and could hit hard, says flu expert Dr. Danuta Skowronski.

Already several parts of the country are reporting sporadic flu activity -- coastal British Columbia, much of Alberta, the Toronto-to-Windsor corridor and the part of the Canadian map where eastern Ontario and western Quebec meet.

The flu virus that has been seen most frequently to this point is H3N2 -- a strain that is especially hard on the elderly. Winters when H3N2 is the dominant flu strain often make for bad flu seasons.

It is still early, and things could change. Influenza is, after all, highly unpredictability. But Skowronski, of the British Columbia Centre for Disease Control, warns that people ought to be thinking about getting vaccinated, and in particular getting the vaccine early in the roll out.

"Since you're picking up these early signals, what you want to do is maximize benefit, minimize risk. And there is only benefit to be derived in making sure that people don't delay getting available vaccine this season," says Skowronski.

One of the problems she foresees is that the H3N2 component of the vaccine being offered in the Northern Hemisphere is not optimal. It's a mismatched, in the language of flu vaccine.

Vaccine strains for our winter flu shots were chosen last February, before last winter's flu season was over. It's always done that way -- it takes months to make, bottle and ship the vaccine we use every winter.

Last February, the viruses circulating seemed to be quite similar to those that were in the 2013-14 flu shot. So manufacturers were told to make this year's flu vaccine using the same strains.

But when the experts who select the vaccine strains met at the World Health Organization in September to pick those that should go into the Southern Hemisphere winter 2015 vaccine, they saw that a new version of H3N2 had emerged.

The viruses had "drifted" -- changing their outer appearance in a bid to evade immune systems that had seen H3N2 before. That means the H3N2 component of the vaccine generates antibodies that may not recognize the new viruses as well.

"The emergence of a new drift strain means that we may have more intense H3 activity this year. And we're also starting to pick up early H3s emerging as the dominant player very early on in the season," says Skowronski.

"H3 is particularly harsh on the elderly. So those (factors) in combination make us pay attention to this virus and the early signals from our surveillance."

The mismatch is not reason to forgo a flu shot this year, she suggests. It is known the vaccine offers some cross protection against viruses that aren't identical to the ones in the shot. And the three strain vaccine also protects against H1N1 viruses and influenza B as well -- though the B strain is probably also a mismatch.

But people who do get vaccinated should understand they may still be vulnerable, and take precautions, Skowronski says. That means things like washing your hands frequently and staying home when you are sick. And if you think you are coming down with influenza, see your doctor quickly to ask about whether you should take one of the flu antiviral drugs.

All of this is especially true for the elderly and those with contact with the elderly, Skowronski says.

So when and where can you get a flu shot?

Most provinces and territories are getting their campaigns going in the next couple of weeks and some -- like Ontario -- have already started to vaccinate residents of long-term care facilities.

"Needles have gone in arms already," says Dr. David Mowat, the province's interim chief medical officer of health.

Alberta's program begins Oct. 20, Nova Scotia's starts Oct. 21 and Ontario's program for the general public commences on Oct. 23. Yukon will start its vaccination effort on November 3; a list of clinic dates and locations will go on the ministry of health's website on Oct. 17.

In fact, the websites of your provincial, territorial or local public health department are the place to go for information about when and where flu vaccinations will start where you live.

A page on the website of the Public Health Agency of Canada (you can find it here: http://www.phac-aspc.gc.ca/im/ptimprog-progimpt/fluvacc-eng.php) outlines who gets flu shots for free in Canada, by province and territory.

At this point only Quebec, British Columbia and New Brunswick don't have universal programs where vaccine is free to all comers. And those three offer free vaccine to large numbers of their populations, including the elderly, children, pregnant women and health-care workers.

As for where to get a flu shot, the options are greater these days than they ever have been. In many jurisdictions, pharmacists have joined family physicians, workplace clinics and public health clinics in delivery of flu vaccine.

This year's supply should be ample, provincial officials say.

Canada's main supplier, GlaxoSmithKline (GSK) had a production problem at its facility at Ste. Foy, Que., that resulted in them cutting the amount of vaccine they could provide this year by two million doses or 17 per cent of the total Canadian purchase.

But the federal government -- which bulk buys flu vaccine for the provinces and territories -- got additional supply from other manufacturers. They didn't quite fill the gap; in total provinces and territories will have about 800,000 fewer doses than they had originally ordered.

However, most had increased their purchase order for this winter over what they had used last year, after a late season demand for vaccine last winter forced several to scramble to try to find more. Alberta, in fact, ran out.

Dr. Gerald Predy, senior medical officer of health for Alberta Health Services, says the province wants to build on last year's demand. It ordered two million doses for this year, up from about 1.3 million last year.

"We don't anticipate supply being a problem," he says.