A COVID-19 vaccine supply shortage has forced Region of Waterloo and Wellington-Dufferin-Guelph Public Health to pause clinics.

Waterloo Region's clinic stopped administering doses on Friday.

"We did receive supply this week already, but that's dedicated to the long-term care homes and retirement homes," said WRPS Deputy Chief Shirley Hilton, who is leading the local vaccine task force.

Residents in those homes will get their second doses at mobile clinics starting Wednesday.

"When we know our allocation is arriving, we will provide information as it relates to the opening of the Grand River Clinic," Hilton said.

Ret. Gen. Rick Hillier, who is leading the provincial vaccination plan, visited Guelph on Monday.

"We are in a bit of a drought, there's no question," he said. "Yesterday I was in Guelph and visited the public health unit in Guelph and looked at their mass vaccination site, which was empty."

Medical Officer of Health Dr. Nicola Mercer said the site was empty because they need to wait between doses and they have to work with current supply. Second doses for care home residents start Thursday and are expected to wrap up by Feb. 24.

It's one of the few units that has two different brands of vaccines.

"For those homes that had Pfizer, we are giving the 21 days," Dr. Mercer said. "For the Moderna, they are going in at 28 days."

Officials from both units said they're doing the best they can with their current supply. They both have plans in place for mass vaccinations later this year.

Waterloo Region will have three fixed locations and mobile clinics.

Wellington-Dufferin-Guelph has eight sites in the works.