Some health authorities across the country have tossed out hundreds of doses of the swine-flu vaccine because of miscalculations over how many of the time-sensitive dosages are needed at community clinics.

Officials at some of the larger health districts, including Toronto and Halifax, say they have thrown out about one per cent of the total vaccine they’ve administered because of the dosages’ 24-hour shelf life. In Toronto, that means close to 500 doses of the adjuvanted vaccine have been disposed of even as people remain shut out of the priority groups entitled to receive the shot.

“We reconstitute as much vaccine as we think we’re going to need, but sometimes our numbers are a wee bit off,” said Ameeta Mathur, manager of the vaccine program for Toronto Public Health. “Once it’s in the syringe from the vial and it’s not used, we have to dispose of it.”

Mathur said there is little information on the stability of the vaccine once it has been reconstituted and drawn into a syringe. Once the solution is in the syringe, she said it can’t be put back in the vial nor can they use syringes the next day because of the lack of data on the vaccine’s stability.

A Department of Health official in Alberta said he didn’t have numbers on the level of waste, if any.