Packages containing the two components of the H1N1 flu vaccine sit in a box at a distribution centre for medical practices in Vancouver, B.C. (Darryl Dyck/Canadian Press)

It's normally a complicated and lengthy process to get new drugs approved in Canada. After years of research and development, a drug company is required to conduct extensive clinical trials to back up its claims that the drug will work the way the company says it's supposed to, before it can submit it for approval.

Once the data's in, the company has to assemble the appropriate paperwork — the New Drug Submission — and ship it off to Health Canada's Therapeutic Products Directorate branch. If everything's in order, and Health Canada's satisfied that the drug's benefits will far outweigh its risks, it takes an average of 18 months for approval to come through.

It helps if the drug has already been approved in the United States.

That's the story for virtually all drugs — including vaccines. Yet it took only a few months for Health Canada to give the go ahead to Arepranix H1N1. That's the vaccine GlaxoSmithKline has developed exclusively in the Canadian fight against the swine flu pandemic.

The reason is that Section 30.1 of the Food and Drugs Act gives the minister of health the authority to fast-track a drug, "to deal with a significant risk, direct or indirect, to human health, public safety, or the environment."

GlaxoSmithKline makes most of Canada's flu vaccines. Normally, it takes the company about six months to produce a season's flu vaccine — once a particular strain of virus has been identified.

The process of developing the swine flu vaccine took less time than that. The process consisted of five major steps:

Identification of virus: it takes 24 hours to determine whether a particular sample being tested is swine flu virus.

Development of a primary seed: developing the base material for the development of a vaccine takes about four weeks. The step is conducted by the World Health Organization. The seed is then distributed to vaccine makers around the world.

Development and production: after the safety testing and preliminary development work is completed, the production process takes about 12 weeks.

Testing: approximately six weeks was set aside to make sure the vaccine did not need to be altered — and was safe for people. Among the tests was a small clinical trial.

Review and authorization: further review of data by Health Canada added another week to the process.

Close monitoring

The federal government gave the green light to Arepranix H1N1 on Oct. 13, 2009 — on an interim basis — based on limited clinical testing in humans. Final approval came on Oct. 21, 2009 — and clinics began operating within days.

Approval was granted on the condition that GlaxoSmithKline agree to post-market commitments. These include sharing the results of ongoing clinical trials and close monitoring of how the vaccine is working.

Health Canada says there have been few side-effects to the vaccine. The most common is pain at the injection site. It notes that with most vaccines, the rate of serious reactions is about one for every 100,000 people vaccinated. For seasonal flu vaccines, it's closer to one for every one million people vaccinated.

Serious adverse events can include life-threatening illness, hospitalization, disability or death, like a severe allergic reaction, paralysis, or a seizure. The agency says that people with serious egg allergies should not have the swine flu vaccine. However, if you have a mild egg allergy, you should check with your doctor to see if the vaccine is safe for you.

Like all drugs, what goes into the swine flu vaccine must be listed on its packaging. However, since most consumers will not be directly buying the vaccine, we won't be seeing the packaging. GlaxoSmithKline's detailed product information leaflet is available on the company's website.

Some unadjuvanted available

The swine flu vaccine contains an adjuvant, which is a substance that boosts an individual's immune system and increases their response to a vaccine. Adjuvants have been used for several decades — but this is the first time one has been approved for use in a flu vaccine.

The adjuvant used in the H1N1 vaccine was tested in about 45,000 people worldwide before it was approved. The World Health Organization has found no significant safety concerns or barriers to using the adjuvant.

Health Canada has ordered just under two million doses of the vaccine without the adjuvant. While the agency says vaccine with the adjuvant is safe for pregnant women, it's providing some unadjuvanted vaccine for those who have concerns.

Both vaccines — with and without adjuvant — contain trace amounts of thimerosal, which is a form of mercury. The unadjuvanted vaccine contains 50 micrograms of thimerosal while the adjuvanted vaccine has 5 micrograms of thimerosal. The 50 micrograms is within the daily limit recommended for environmental exposure to mercury. There's significantly less mercury in the vaccine than in a can of tuna.

Timeline by Christine Peloquin, CBC News