TORONTO — As swine flu vaccine becomes available in coming months, boosting compounds known as adjuvants may stretch out limited supplies. But they also pose special challenges for vaccine regulatory agencies in places like Canada and the United States.
Neither country has licensed flu vaccines with adjuvants in them before, making the addition of the oil-and-water emulsions a potential hurdle to plans to fast-track pandemic vaccines. Fast-tracking is based on the premise the vaccine is the same as seasonal flu shots, just targeting a different virus.
For that reason, officials in the U.S. have hinted they would rather not use adjuvants, unless the compounds are needed to ensure adequate supply for Americans. With manufacturers complaining of low yields as they attempt to make the new vaccine, that need remains a possibility, officials admit.