Health officials are investigating the possibility that an elderly Quebecer died from a serious reaction to H1N1 flu vaccine.

The person died sometime in the past three weeks, but Quebec's health ministry refused to give additional details.

Dr. David Butler-Jones, Canada's chief public health officer, said there is no conclusive evidence yet that the death is related to the flu shot.

"It's important to remember that just because a medical event follows vaccination, it may not have been caused by the vaccination; it may have been caused by other factors, as unfortunate events continue to occur with or without vaccine," he told a news conference Tuesday.

The total number of deaths in Canada resulting from complications related to the flu has reached 198.

Butler-Jones stressed that only a small number of Canadians have suffered serious side effects from the swine flu shot.

Of the 6.6 million doses of H1N1 vaccine that have been given across the country so far, there have been just 36 serious adverse reactions.

More serious side effects related to the shot include allergic reactions, fevers and convulsions. Milder reactions such as nausea, soreness, headaches and fever have also been reported.

Student vaccinations

Most school boards in Quebec will begin transporting students by bus to vaccination centers this week.

So far, more than 1.5 million Quebecers have been vaccinated, and health minister Yves Bolduc says everyone who wants to get the flu shot will get one before Christmas.

Bolduc is committed to the promise despite the fact that deliveries of the vaccine have fallen well short of the number of doses Quebec was promised.

In Quebec City, clinics were closed Monday and Tuesday because of the vaccine shortage.

But Bolduc said he believes the plan to give the shot to everyone who wants it before Christmas will be successful if the deliveries double and the demand isn't too big.

"If you have a ratio of maybe 50 or 60 percent, we can offer the vaccine to almost every one," he said.

With files from CTV.ca News Staff