WATERLOO -- Nearly 1,000 doses of the Moderna COVID-19 vaccine sent to pharmacies have been thrown out in Waterloo Region.

According to a local vaccine expert, about 990 doses of the Moderna vaccine at local pharmacies went bad in recent weeks.

Last month, the sudden decline in people wanting that particular brand of COVID-19 vaccine left pharmacies in the area scrambling.

"Demand really dropped and they were left with several vials and hundreds of doses," said Kelly Grindrod, an associate professor at the University of Waterloo's school of pharmacy and pharmacy lead for the region's vaccine task force.

Grindrod said pharmacies worked with public health to get thousands of doses at risk of expiring to the Pinebush mass vaccination site in Cambridge.

"We know that there about 3,300 doses that were brought from pharmacies to the Pinebush clinic and Pinebush was able to use about 70 per cent of those doses," she said.

When vials of Moderna are thawed from the freezer to the refrigerator, the shelf life is only about a month.

"We've seen across the province a certain amount of doses expired at 30 days when there's no demand there," Grindrod said.

The Region of Waterloo Public Health Unit is not disclosing its wastage of Moderna vaccines originally sent to clinics or family doctors' offices.

The health unit referred a request for that information to the province.

A spokesperson with the Ministry of Health said they will provide an answer in the coming days.

In nearby London, the health unit there admitted last week that about 10,000 Moderna doses had expired.

"Our projection was about 30,000 worth of Moderna wastage, we were able to get it down to 10,000," said associate medical officer of health Dr. Alex Summers. "Again, this was linked to that precipitous drop in demand for vaccine in mid-July."

Grindrod said each Moderna vial contains 14 doses, and pharmacies and doctors are now dealing with sporadic patients wanting the shot.

"They are willing to take the vaccine, do you give a dose at the risk of wasting 13 other doses?" she said.

Grindrod said she expects the province will soon be changing the vaccine rollout to prevent further wastage.

"Now the way we are vaccinating is a bit mismatched with the supply we've got," she said.