While some Americans have already begun receiving a swine flu vaccine, Canadian scientist still have yet to begin testing the Canadian vaccine.

When testing does begin, scientists say it will take at least six to seven weeks to collect data on Canadian test subjects, giving them results in late November, or more likely December. Still, Health Canada continues to stress that the vaccine will be ready to administer to Canadians in November.

All this comes as evidence suggests the second wave of swine flu is already beginning to arrive.

In an email to CTV News, Health Canada's Gary Holub explained that the vaccine approval process that Canada is using will use data from international clinical trials, which were started in early September.

"There is agreement amongst the regulatory authorities of the world who are currently conducting evaluations of pandemic vaccines to share the data that is being generated on the vaccine," Holub explained.

Those trials are testing a vaccine developed in Europe for avian flu (H5N1), that is being modified to fight H1N1. The vaccine has been approved already in Europe. But scientists in Canada are still waiting for the green light to begin testing the vaccine here.

As of late today, a scientist involved in the H1N1 studies told CTV that the Bureau of Biologics (HC) gave a Letter of No Objection last week.

But approval to begin the tests also must come from the U.S FDA, because the Canadian studies are being done jointly with American centres.

"Our study hasn't started," Dr. Joanne Langley of Dalhousie University told CTV News on Monday. She said she hopes to have FDA approval this week, and to begin injecting test subjects October 14th.

When CTV called another test site in Ontario, we were told vaccine injections for the purpose of research would not begin until October 21.

Researchers say it will take 6 to 8 weeks to complete Canadian tests of the vaccine which would mean that data won't be available until the last week of November, or the first week of December at the earliest. But Health Canada has said it will make the vaccine available mid November -- meaning it will do so without Canadian results on safety and efficacy. Officials have said they can approve its use based on studies from other countries.

Health Canada is expected to approve the vaccine based on the European trial data, so that vaccine programs can begin in November, as promised. They will then monitor the safety and effectiveness of the vaccine by also reviewing the Canadian study data.

In an email, Canada's pandemic flu vaccine manufacturer, GlaxoSmithKline, said "sites for the clinical trials have been selected and (we) are starting recruitment activities to identify potential participants. GSK Canada expects to start clinical trials in Canada in early October."

Health Canada is expected to approve the vaccine based on the European trial data, so that vaccine programs can begin in November, as promised. They will then monitor the safety and effectiveness of the vaccine by also reviewing the Canadian study data.

Even with the vaccine's expected arrival in mid-November, some public health experts are still worried that the vaccine may come too late in the flu's "second wave," which may have already peaked by mid-November.

Infectious diseases expert Dr. Neil Rau told CTV News he wonders whether Canada's approach has been ideal.

"I think the U.S. made the right decision to focus on those at higher risk and in return for that they used an old method to make the vaccine which did not incur time delays. We went for a different approach where we tried to vaccinate everyone but we used a newer style vaccine which incurred delay and that's unfortunate," Rau said.

Nasal spray in U.S. ready first

For now, there is not much H1N1 vaccine available in the U.S., but more should trickle in over the coming weeks, becoming available at a rate of about 20 million doses a week.

Seasonal flu vaccination programs are also underway in the U.S., having begun last month.

The first vaccine to be administered in the U.S. is FluMist, a nasal spray from AstraZeneca unit MedImmune. MedImmune has had especially good production of its H1N1 vaccine and has been the first to make doses available.

AstraZeneca Canada is still seeking Health Canada's approval to market FluMist in Canada.

The U.S. government has ordered about 250 million doses of both injectable and nasal spray vaccine from five companies: Sanofi-Aventis SA; CSL Ltd; MedImmune; Novartis AG and GlaxoSmithKline.

Washington will provide the vaccine to about 90,000 distributors, including doctor's offices, retail chains and state health departments for free, but clinics and retailers may charge to administer them.

Pregnant women, health care workers and people with special health conditions, including heart disease and diabetes, are supposed to be the first to get the vaccine. There will no enforcement of this, though, so it will be up to those administering the vaccine to decide who should receive it first.