KITCHENER -- Region of Waterloo Public Health has paused its COVID-19 vaccine clinic due to a supply shortage.

The clinic will pause until Jan. 24, the region said in a news release.

Pfizer announced last week that it is retooling its production line so that it can produce more doses of the vaccine in the future. Officials with the region said that announcement means they need to rework their plan at the Grand River Hospital clinic.

The clinic will be administering second doses of the vaccine when it reopens on Jan. 24. Officials said everyone will get their second doses between 25 and 28 days from their first dose, which is consistent with Health Canada guidelines.

“We will continue to focus on administering doses to those in long-term care homes and high risk retirement homes through our mobile clinic team. Once our allocation is increased, we will be ready to fully resume our vaccination plan," said Deputy Chief Shirley Hilton, the region's COVID-19 vaccination lead.

The region said there will be a temporary slow-down in vaccinations in January and early February due to the lack of supply. Officials plan to continue prioritizing long-term care and retirement home residents, along with staff and essential care partners.

Kelly Grindrod, an associate professor at the University of Waterloo's School of Pharmacy said shifting focus to long-term care homes is the right move.

"It makes a lot of sense, when resources are scarce, that there's a focus shift to getting that priority group done," Grindrod said.

Hospital staff and physicians likely won't receive their first dose of the vaccine until supply increases.

Ontario officials knew the Pfizer supply would suffer in the short term, but didn't expect the cancellation of next week's shipment.

"We were led to believe that we would get 15,000, that figure is now zero," Gen. Rick Hillier said. "Obviously it's going to slow down what we can do. We're going through those figures right now. Our number one priority is the long-term care homes across the province."

Region of Waterloo Public Health officials reported more than 1,100 long-term care residents received their first dose of the vaccine on Monday. More than 4,400 residents, staff and essential caregivers have been inoculated since the vaccine arrived in the region last month.

Natalie Mehra with the Ontario Healthcare Coalition said the residents and staff should have gotten their initial doses sooner.

"The focus is right, the slowness of the rollout is very, very disturbing," Mehra said. "It needs to happen much quicker."

Grindrod said this delay feels more difficult because it's the first one in what's expected to be a long rollout.

"That's the effect we are feeling right now," Grindrod said. "A lot of people who are really first in line to get the vaccine are still having to wait."

Wellington-Dufferin-Guelph Public Health said it's still moving forward with the vaccine supply on hand, but said "changes to the vaccination clinics and some rescheduling of appointments will be unavoidable."

That region will also continue to prioritize long-term care and retirement homes.

Provincial officials said doses of the Moderna vaccine originally earmarked for Toronto will now be reallocated to more areas.

It's not known if some of those doses may come to Waterloo Region.

With files from CTV News Kitchener's Nicole Lampa