TORONTO - Canada is in discussions with pandemic vaccine maker GlaxoSmithKline and with the World Health Organization about what to do with the country's expected surplus of H1N1 vaccine, the head of the Public Health Agency of Canada said Wednesday.

By the end of this week nearly 24 million doses of vaccine will have been shipped to provinces and territories, which are reporting demand for H1N1 shots is subsiding.

But that is only half of the country's total order of 50.4 million doses, placed when it was thought two shots per person might be needed for protection.

While public health officials still hope to be able to persuade more Canadians to get vaccinated, the possibility exists that the country may have as much of half of its vaccine order go unclaimed.

"Obviously our hope is that far more people will be immunized because we're far from done (with) this virus," said Dr. David Butler-Jones, head of the public health agency and Canada's chief public health officer.

But if that doesn't happen "vaccine will not be wasted." he insisted. "There's a tremendous demand around the world."

Federal officials have been refusing to say what they will do with the excess vaccine. While many other developed countries have pledged vaccine to the World Health Organization for redistribution to developing countries, Canada has held back, to the puzzlement of the country's peers.

And Butler-Jones appeared to be hinting the country would continue to do so for a while, noting there will still be need for vaccine at the end of Canada's winter, when the Southern Hemisphere heads into its second flu season with this new virus.

"There are needs now and there are needs ongoing because we will be coming into the Southern Hemisphere's (winter) where many of the poorest countries exist," he said.

"Our spring is their fall, moving into their season. That's an ongoing discussion that we're having with WHO and Canada will be there."

Butler-Jones said the rate of vaccine uptake across the country varies.

Some provinces are reporting the percentage of people vaccinated is in the low 30s, but Quebec has topped 40 per cent, he said. Rates are highest in the three northern territories, which have vaccinated between 50 and 60 per cent of their populations.