TORONTO -- Hospitals networks across the Greater Toronto Area are adjusting the rollout of the COVID-19 vaccine and some are temporary closing immunization clinics due to a supply shortage.

The vaccine clinic at Trillium Health Partners hospital (THP) in Mississauga will close at the end of Friday. The hospital network says it is implementing direction from Ontario’s chief medical officer of health to expand the second dose interval for the Pfizer-BioNTech from 21 to 35 days.

“Long-term care and retirement home health care workers and THP staff, who have not already received their second dose, will be rescheduled from a 21-day to a 35-day interval,” Trillium Health said in a statement to CTV News Toronto.

Trillium Health Partners started administering the vaccine on Dec. 21 and by the end of Friday, more than 13,500 doses have been administered.

“I was bit teary when I heard I was going to be able to come under the wire, many of my colleagues don’t have that same opportunity,” registered nurse Samantha MacNeil said before receiving her second dose. “Definitely, I’m feeling much more protected and safer to come home to my family as well.”

The clinic is expected to reopen on Feb. 13, coinciding with the 35-day interval between doses.

The delays are due to Pfizer-BioNTech pausing production at a plant in Belgium in order to expand its manufacturing capacity.

The vaccine shortage has forced the province to refocus it’s distribution plan.

Other GTA hospital adjust rollout

William Osler’s vaccine clinic will temporarily close staring on Saturday and will reopen on Feb. 13 to administer second doses for health care workers to align with the new interval.

“As per the ministry's most recent directive to extend the second dose interval from 21 to 35 days, all second dose appointments pre-scheduled at Osler from Jan. 30 onwards will be shifted to a 35-day interval,” William Osler Health System spokesperson Donna Harris said.

Since opening the clinic in December, Osler has administered more than 10,000 doses of the Pfizer-BioNTech vaccine.

Sunnybrook Hospital has been offering only second doses since Monday.

“As of tomorrow, we will be offering only second doses to residents in long-term care and high risk retirement homes,” said Criag DuHamel, vice president of communications and stakeholder relations.

DuHamel told CTV News Toronto the hospital has enough vaccine to get into next week, but the main challenge is having second doses for health care workers.

“We're not sure yet when we're going to be back online with those doses.”

MacKenize Health in York Region, paused first doses for the vaccine a week ago as per the provinces direction.

“Beginning Saturday, all patient-facing staff, physicians and active volunteers who have already received their first dose of the vaccine will have their second dose appointments rescheduled to adhere to the 35-day schedule as directed by the ministry of health,” Christina Cindric, Senior Communications consultant said in a statement.

For residents of long-term care, high-risk retirement and First Nations elder care homes, the dosing interval is maintained at 21 to 27 days.

According to the ministry of health, 327, 455 total doses have been administered and 61,679 people have been fully vaccinated.