Those at greatest risk first in line for swine flu vaccine

Canada’s public health officials are recommending people who are at greatest risk of complications from swine flu – people under 65 with chronic conditions, pregnant women, children six months to less than five and those living in remote and isolated settings and communities – should be among the first to be vaccinated.

The priority list released by the Public Health Agency of Canada is designed to decrease sickness and deaths and to try and maintain the smooth functioning of society during an anticipated fall outbreak of human swine flu.

But the list comes amid growing concerns shots will arrive too late to immunize vulnerable groups and hold back a fresh wave of illness.

The first vaccinations are not expected to begin until early November.

Reporting in the journal Science last week, American researchers warned substantial spread of H1N1 is expected to begin this month, with the epidemic peaking in mid to late October.

Regulators have been working on ways to reduce the time required for getting the vaccine out, raising concerns people will be exposed to an incompletely tested vaccine.

"We’re rushing to get them out in time so the testing is going to be for a very short period of time, and on a comparatively small sample of people," says Arthur Schafer, director of the Centre for Professional and Applied Ethics at the University of Manitoba.

"The vaccine will be less well tested, and the entire Canadian supply with be adjuvanted," he said.

Adjuvants are compounds added to vaccines that boost the effect of the dose. "The adjuvant chemical potentially makes this a much riskier drug to give to children or pregnant women," Schafer says.

On Monday, vaccine maker GlaxoSmithKlline announced its pandemic vaccine induced a strong immune response after a single dose in a trial involving 130 healthy adults. The company is conducting 15 other studies in more than 9,000 volunteers across Europe, Canada and the U.S.

Canada ordered 50.4 million vaccine doses from GlaxoSmithKline, based on the assumption two doses would be needed and that 60 per cent of the population would need it, or want it.

But so far, the pandemic hasn’t reach the overall level of severity planners had predicted, or expected from a pandemic flu. Officials also can’t be sure, so far, the overall mortality or severity is much different from regular seasonal flu.

Most patients infected with the pandemic virus have mild symptoms and recover fully within a week, even without medical treatment. The "case fatality rate" has been estimated at around 0.4 per cent, which is higher than the average seasonal flu, but on the same order of magnitude.

However, experts can’t predict who is likely to have severe outcomes. H1N1 can cause acute respiratory distress syndrome, viral pneumonia and multi-organ failure.

Dr. David Butler-Jones, Canada’s chief public health officer, has said the vaccine "is clearly the one strategy that allows us ultimately to prevent spread of the pandemic."

Vaccinating all people in remote communities will also be a priority, he has said.

The opposition parties have been critical of the federal government’s handling of the pandemic, particularly in remote First Nations communities, and accuse the Conservatives of dragging their feet on pandemic planning over the summer.

U.S. public health officials issued their recommendations for who should receive the vaccine at the end of July.

They include pregnant women; people who live with, or care for children younger than six months old; health care and emergency medical services personnel; children and young adults up to 24 years old; and adults aged 25 to 64 with underlying health problems or compromised immune systems.

The groups total approximately 159 million Americans.

As of Sept. 15, a total of 76 deaths related to H1N1 had been reported in Canada since the outbreak began in April.

Research shows a strikingly high prevalence of obesity in intensive care patients infected with H1N1.

A new study of the first 32 people admitted to an intensive care unit in Spain with swine flu found 10, or 31 per cent, were obese, with a body mass index greater than 30.

Another analysis of 574 H1N1 deaths from 28 countries found diabetes and obesity were the most frequently identified underlying conditions and were found in fatal cases over the age of 20 years.

Obesity alone normally isn’t a risk factor for regular seasonal flu.

H1N1’s attack rate has also been particularly high in young people, with most of those infected under the age of 20.

A national, hospital-based surveillance network is also being put into place to monitor for vaccine-related adverse reactions and measure the vaccine’s impact on H1N1-related hospitalizations and deaths.