Canada's order for a swine flu vaccine must be placed by the end of July if the vaccine is to be availabe in time for the fall flu season. Countries are already putting in orders even though a vaccine for the current strain of H1N1 virus is still in development. (Chuck Stoody/Canadian Press)

Canadian health officials are deciding on how much swine flu vaccine will be needed in the country this fall.

Dr. Arlene King, Ontario's chief medical officer of health, said Monday the order must be placed by the end of the month, and that officials are working on a firm number of how many people will want or need the vaccine.

King noted the whole vaccine order will not be ready at the same time, but said officials expect the vaccine to first become available in mid-November.

At a meeting in Toronto, King told public health units from across the province to factor the H1N1 virus into their back-to-school preparations. Younger people are more likely to fall ill, which means people in campus residences could be at greater risk, she said.

"We know that there's a high degree of susceptibility in persons under the age of 50," King said.

"We know that when people are in close quarters, there is a high risk of transmission. And we know when there isn't adequate infection control … in that setting and good access to medical care, that there's not only a higher incidence of disease but a higher incidence of complications."

Health officials in other countries are considering postponing traditional back-to-school dates to slow the spread of swine flu in the fall.

Keiji Fukuda, WHO's assistant director general for health security and environment, said the first H1N1 vaccines are expected in September and October. The United States expects to begin testing on some volunteers in August, with 160 million doses ready in October.

Up to 40 per cent of Americans could get swine flu this year and several hundred thousand could die without a successful vaccination campaign, according to a new projection by the U.S. Centers for Disease Control and Prevention.

The estimate is about double the number who catch flu in a normal season, which has stepped up the pressure on researchers and pharmaceutical companies to speed up efforts to get a pandemic vaccine ready for the Northern Hemisphere's fall flu season.

Cases rising

In a briefing note on Friday, WHO said the number of human cases of swine flu is "still increasing substantially in many countries, even in countries that have already been affected for some time."

The agency is no longer asking countries to report on the number of cases but to instead watch for spikes in rates of absenteeism from schools or workplaces or a more severe disease pattern, such as a surge in emergency department visits.

The median age of cases is 12 to 17 based on data from Canada, Chile, Japan, U.K. and the U.S., the WHO briefing said, adding that some reports suggest those needing hospitalization and those with fatal illness might be slightly older.

On Monday, the German Health Ministry's official laboratory said swine flu is starting to spread more quickly, with 1,500 new cases registered in Germany over three days last week, bringing the country's total to just under 3,400 cases.

Also on Monday, Israel confirmed its first death of someone infected with the H1N1 virus.

In the Southern Hemisphere, last week Argentina reported 165 fatalities — the second highest number of swine flu deaths after the U.S., according to a posting on ProMed, an online global reporting system run by the International Society for Infectious Diseases. The number of confirmed swine flu cases also continues to increase in Australia and New Zealand, according to health officials.

Vaccine safety trials

The European Medicines Agency, the EU's top drug regulatory body, is accelerating the approval process for a swine flu vaccine, and countries such as Britain, Greece, France and Sweden say they'll start using the approved vaccine possibly within weeks.

In an interview with The Associated Press, Fukuda warned about the potential dangers of untested vaccines, although he stopped short of criticizing Europe's approach outright.

"One of the things which cannot be compromised is the safety of vaccines," he said Friday. "There are certain areas where you can make economies, perhaps, but certain areas where you simply do not try to make any economies."

The European regulator is allowing companies to skip testing of the vaccine on hundreds of people for several weeks or months before approval.

Last week, the U.S government called for the swine flu vaccine to be injected into several thousand volunteers starting in August to assess the vaccine's safety. American officials said results should be ready by the time the U.S. plans to roll out a vaccination campaign in October.

With files from The Canadian Press and The Associated Press