TORONTO -- It's been a bad week for Ontario's vaccine rollout. Multiple clinics around the GTA have said that they are either temporarily shutting down or no longer taking bookings because they don't have enough doses to vaccinate people.

At the same time, some critics charge that there are more than 1 million doses sitting in freezers that could be distributed. They point to the number of vaccines delivered to Ontario and compare it to the number of doses administered.

As of Wednesday night, Ontario had given out a total of 3,528,404 doses, according to provincial data. According to federal government figures which were updated at the same time Wednesday, the province has received 4,852,885 vaccine doses to date.

With Ontario vaccinating at a rate of approximately 100,000 doses per day, the numbers suggest that the province has about 10 days’ worth of supply.

For its part, the province has said that most of the doses that have not been administered are already spoken for, meaning that they are either en route to clinics where they will be administered or are at the clinics and are being held in order to honour booked appointments over the next few days.

A video shared by Health Minister Christine Elliott Wednesday said that Ontario is not “letting a single vaccine sit in a freezer.”

So who’s right?

Three vaccines distributed differently

Speaking with CP24 Thursday morning, Dr. Isaac Bogoch, who sits on the province’s COVID-19 Vaccine Distribution Task Force, said the answer requires “a bit of nuance.”

“When you hear about vaccines in freezers, that doesn't mean that there's a big freezer with a bunch of vaccines sitting in the freezer,” he said. “That means that those are vaccines that we have in the province, that have not yet been administered to people, but have been allocated.”

There are currently three vaccines being administered in Canada: Pfizer, Moderna and AstraZeneca.

Ontario is receiving about 400,000 doses of the Pfizer vaccine per week and 90 per cent of them go directly to public health units and hospitals.

“It shows up like clockwork, it comes in, it's not late,” Bogoch said. “We get 400,000 doses, and at the end of the week, we have very, very little of that (left).”

According to the province, 10 per cent of the Pfizer doses, along with all of the Moderna and AstraZeneca shipments are sent to Ontario’s central distribution facility. They arrive at the facility within about 24 hours of landing in the province. Those remaining Pfizer and Moderna doses are then processed and shipped out to PHUs and hospitals. The AstraZeneca doses are sent to pharmacy warehouses where they are distributed to hundreds of pharmacy locations.

“Moderna gets delayed from time to time. I don't know why, but that's just the way it is,” Bogoch said. “When Moderna gets delayed, sadly, you don't have a ton of Moderna in reserve, and some clinics can get cancelled.”

Moderna shipments arrive in the province roughly every two weeks and according to Bogoch, just about all the doses are used up by the time the next shipment arrives.

The province largely blamed the cancellation of thousands of appointments across the GTA this week on the delay of a large Moderna shipment until the end of the month.

500,000 AstraZeneca doses not yet administered

While there is a supply of AstraZeneca in the province, Bogoch said it is not being taken up as quickly as the province would like, accounting for many of the unadministered doses.

Ontario received an allotment of 583,400 AstraZeneca doses between March 29 and April 4 as part of a U.S. loan deal with Canada. According to the province, 500,000 of those doses have been delivered to pharmacies and doctors’ offices, but have yet to be administered.

“AstraZeneca is, just calling it how it is, not flying off the shelves,” Bogoch said.

“You can get this at about 1,400 pharmacies in the province. The age cutoff is 55 and up and people are getting AstraZeneca, but it's not moving as quickly as the other two vaccines.”

AstraZeneca doses were also sent to some doctors’ offices for distribution.

However provincial officials have said that some delivery channels, such as primary care physicians, take longer to administer doses than others.

Bogoch noted that the province recently added hundreds of additional pharmacy locations where AstraZeneca can be distributed and said he is hopeful that more people will start booking appointments for the shots which are currently being given to those 55 and older in Canada, as per advice from the National Advisory Committee on Immunizations (NACI).

Bogoch said he understands that many people are hesitant to get the vaccine because of concerns around blood clots and may be holding out for a different vaccine, but said that the evidence shows the risk is very low for most people.

“I think if we lowered the age cutoff for AstraZeneca, if we put it into more nodes, like massively expanded it into primary care, and of course enable informed consent — there is still a risk, a tiny risk, but still a risk of blood clotting — you would see much more AstraZeneca in arms and you would move through that stockpile much more quickly.”

Just enough stored to get through a few days

Speaking with CP24 Wednesday, Toronto's top doctor said that the city is administering doses as quickly as it can and is not holding back its supply.

“What I can say when it comes to the notion that there are vaccines sitting in fridges -- that is simply not the case here in Toronto,” Dr. Eileen de Villa said.

Speaking to the situation at city-run clinics, de Villa said Toronto keeps just enough supply on hand to get through booked appointments until the next expected delivery date.

“The vaccines we have take us through to covering the clients that we have booked for the next five days, which is when we receive the next delivery of the vaccine to allow us to see clients for next week,” she said.

Roughly 10,000 booked appointments were cancelled at two hospital-run clinics in Scarborough this week after the Scarborough Health network said it did not have enough supply to honour the appointments.

However it is not clear why some clinics continue to have a supply and others do not.

Local public health units are responsible for managing and overseeing the distribution and administration of vaccines for their regions.

“Vaccination clinics are expected to manage their bookings against what is allocated, especially given the ongoing disruptions in Moderna supply from the federal government,” the premier’s office told CP24.com.

Speaking at a news conference Thursday, Dr. Dirk Huyer, who coordinates the provincial outbreak response, echoed the idea that there are no stockpiles of vaccine sitting somewhere.

“Vaccines don't sit around,”Huyer said. “They don't rest in provincial freezers or coolers on a basis. They're allocated out and they are booked, there are appointments booked for weeks out to be able to provide vaccine to others.”

On Wednesday, 105,430 people received a shot in Ontario, down about 7,000 doses from Tuesday when the province gave out 112,817 jabs.