Health-care workers are at the front of the line for a pandemic vaccine. (CBC)

Health-care workers in every country should be immunized against the swine flu pandemic strain, the World Health Organization recommended Monday.

"The [group of experts] recommended first that health-care workers should be immunized in all countries in order to retain a functional health system as the virus evolves," Marie-Paule Kieny, WHO director of the Initiative for Vaccine Research, told a news conference in Geneva.

"In terms of the other groups, it depends on the strategy a country wants to follow."

Kieny said health-care workers are a priority since their exposure to the H1N1 vaccine may be greater and because they will also need to continue caring for people sickened by other diseases during the pandemic.

Governments will make their own decisions on immunizing other groups that observations from several countries suggest are at greater risk of hospitalization or death from swine flu, including:

• Pregnant women.
• Those over the age of six months with a chronic health condition such as asthma or other chronic lung disease, and obese people with a body mass index greater than 30, and particularly greater than 40.
• Healthy children and healthy elderly.

The agency's experts did not place a priority ranking for these other groups, saying it would be up to countries to decide on their strategy, such as targeting children to mitigate spread or focusing on reducing deaths and disease, Kieny said.

Kieny said vaccine manufacturers have reported "poor" vaccine yields — 25 to 50 per cent of normal levels — of swine flu virus grown in eggs, the most common way of producing vaccines.

Canadian vaccine coming in October

WHO's laboratory network is trying to generate new vaccine viruses from samples isolated from patients that will hopefully produce higher yields, Kieny said, noting the yields are sufficient for making batches of experimental test vaccine.

Vaccine manufacturers and regulators are working to make the vaccine available as soon as possible, starting in September and October, Kieny said.

Regulators need to check the safety and effective dose of a vaccine in clinical trials before licensing it for widespread use, but many countries have provisions for emergency use based on pharmaceutical rather than clinical data. Countries will decide on whether to use the vaccine under these emergency provisions, depending on how the epidemic evolves, Kieny said.

In Canada, GlaxoSmithKline expects the first doses of swine flu vaccine will be available in October. It could be early next year before the pandemic vaccine rolls out for widespread use across the country.

Canadian doctors will be given guidelines this fall to help them determine who is a priority patient.

Many of the guidelines are already in place, and will be reinforced for the fall, said Dr. Michael Gardam, director of infectious diseases prevention and control at the Ontario Agency of Health Protection and Promotion.

He said the advice doctors expect to receive includes, "who to give the vaccine to, but also advice in terms of who to test, when to potentially treat people, things like that."

94,512 cases worldwide

WHO expects to offer more information in September when it meets to determine what strains to include in seasonal vaccines for the northern hemisphere. So far, it's expected that people who wish to be vaccinated would receive one seasonal shot and two doses of pandemic vaccine.

A total of 94,512 cases of swine flu have been reported worldwide, according to numbers released by the WHO on Monday. Of those infected, 429 people have died.

In Canada, there have been 9,855 cases, including 39 deaths. Of the Canadian cases, 138 new cases were reported Monday by the federal public health agency. The new cases include:

• 57 in British Columbia.
• 29 in Alberta.
• 7 in Saskatchewan.
• 10 in New Brunswick
• 26 in Nova Scotia.
• 4 in Northwest Territories.
• 5 in Nunavut.