Parents of school-age children who have been wondering whether their kids would need one or two doses of H1N1 vaccine finally have their answer: one half-dose is enough.
The Public Health Agency of Canada has decided that for most healthy kids between the ages of three and nine, one half-dose of adjuvanted vaccine is enough to confer protection.
But kids older than six months and younger than three should still receive two half-doses of vaccine, administered at least 21 days apart, as has already been recommended.
And children between three and nine who have chronic health conditions, such as asthma, lung disease, diabetes, and other conditions should also still receive two half-doses.
In fact, PHAC advises, they should receive their first dose "as soon as possible."
Children over the age of 10 still need just one full dose of vaccine.
The updated recommendations reflect findings from research out of Europe that suggested that a single half-dose of adjuvanted H1N1 flu vaccine for healthy children seems to provide a good level of protection.
Dr. David Butler-Jones, Chief Public Health Officer for Canada, noted in a news release that the change in recommendations is not only good news for parents of healthy children, it's good for all Canadians, since it means that more resources can now be devoted to immunizing other priority at-risk populations.
It also means that the vaccine will be available for the general public sooner.
The agency noted that further adjustments to the vaccine dosage recommendations may still be made once the results of additional research and clinical trials on vaccine effectiveness are available.
Late last month, the World Health Organization said the data it had reviewed so far suggested a single half-dose of vaccine was enough to immunize children under the age of 10.
The data it reviewed came from a study of 51 young children in Spain who received GlaxoSmithKline's adjuvanted vaccine. That's the same vaccine Canada is using.
The study showed that even in the youngest age group (kids six months to 35 months), one half-dose generated antibody levels that provided good protection.
Since the WHO changed its recommendations, PHAC has been under pressure to and issue its own recommendations to Canadian parents.
Butler-Jones conceded earlier this week that the Spanish study was a "very small sample." So he said his agency was also gathering expert opinion from pediatricians, experts in vaccine, and others.
With most flu vaccines, children are given two flu doses. That's because their immune systems are not fully developed and evidence suggests they don't mount a strong enough immune response from just one dose.
The H1N1 swine flu vaccine is different, though, because it contains an adjuvant, which provides a wider and more durable antigenic response.
