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Vaccine guidance updated, Tam assures efficiency of AstraZeneca

Friday, June 18, 2021 @ 11:36 AM | By Amanda Jerome

On June 17, Canada’s chief public health officer, Dr. Theresa Tam, provided an update on vaccine guidance and announced that Canada is seeing “seeing impressive numbers in vaccine coverage.”

“More than 30 million doses have been administered to date, and as of June 12, 73 per cent of the population in Canada age 12 and older has rolled up their sleeves,” she said.

As of June 11, Tam noted, there have been “7,408 reports of adverse events following immunization; these include any medical event that occurs following immunization, but isn’t necessarily related to the vaccine.”

Over 1,000 of these reports, about one in 18,000 doses administered, Tam explained, “were considered serious, such as a severe allergic reaction and vaccine-induced Immune thrombotic thrombocytopenia (or VITT).”

She then turned to the updated recommendations on first and second doses of COVID-19 vaccines authorized for use in Canada, which were released by the National Advisory Committee on Immunization (NACI) on June 17.

“NACI reviews new scientific evidence on COVID-19 vaccines on an ongoing basis and revises its guidance on the use of authorized vaccines accordingly,” she emphasized.

Tam noted that in making its recommendations, NACI considered: “the increasing availability of mRNA vaccines in Canada; emerging evidence suggesting better immune responses when a first dose of the AstraZeneca vaccine is followed by a second dose of the Pfizer-BioNTech or Moderna mRNA vaccines; the risk of VITT associated with viral vector vaccines but not associated with mRNA vaccines; and principles of ethics, equity, feasibility, and acceptability.”

“Based on the most recent evidence,” she said, “NACI recommends that an mRNA vaccine, such as Pfizer-BioNTech or Moderna, should be offered to start a vaccine series, unless there is a contraindication, for example an allergy to one of the mRNA vaccine ingredients, or if an mRNA vaccine is not available.”

She stressed that NACI’s earlier recommendation, “that people who wanted earlier vaccination could receive a viral vector vaccine rather than wait for an mRNA vaccine, reflected the limited supply of mRNA vaccines at the time and the imperative of protecting vulnerable populations from serious illness and death during a time of resurgence of COVID-19.”

“That recommendation has now evolved,” she explained.

Tam announced that for second doses, “NACI recommends that individuals who received a first dose of an mRNA vaccine, such as Pfizer-BioNTech or Moderna, should be offered the same mRNA product for their second dose. If the same product is not readily available, or the product used for the first dose is unknown, another mRNA vaccine is considered interchangeable and should be offered to complete the series.”

“In addition, an mRNA vaccine should now be offered as the second dose for individuals who received a first dose of the AstraZeneca/COVISHIELD vaccine. This change is based on emerging evidence indicating a potentially better immune response from this mixed vaccine schedule and to mitigate the potential risk of VITT associated with viral vector vaccines,” she said.

Tam emphasized that “people who received two doses of AstraZeneca/COVISHIELD vaccine can rest assured that the vaccine they received provides good protection against infection and very good protection against severe disease and hospitalization.”

“We are aware of and are closely monitoring reports of rare cases of myocarditis and pericarditis — heart inflammation — following vaccination with mRNA vaccines. NACI is closely following these reports, as are scientific experts at the Public Health Agency of Canada, Health Canada, and the provinces and territories,” she said, adding that there is no “clear association yet established between vaccination with an mRNA vaccine and this condition.”

Tam reminded everyone that “despite Canada’s tremendous progress in getting people vaccinated, we are not out of the woods.”

“We all need to complete a full vaccine series to give our immune systems the best possible shot at fighting off infection from COVID-19. So, get that second dose as soon as it’s offered to you,” she stressed.

During the Q-and-A session, Tam addressed questions from the media regarding Canadians’ displeasure at NACI’s past advice on AstraZeneca, which has changed over time.

She noted that NACI has been “extremely transparent and extremely careful” with its advice.

“It is difficult, of course, working in this environment of change and also to catch up with the recommendations, so I totally recognize that this is difficult for many. But what I would say is, those who have received two doses of the AstraZeneca/ COVISHIELD vaccine, you’ve been provided with good protection against infection, but more importantly AstraZeneca provides good protection against severe illness and hospitalization,” she stressed.

The press also asked Tam what confidence she has that people who got the AstraZeneca vaccine won’t face barriers in travelling to the U.S.

She noted that “every country has authorized different vaccines” and governments are “making different policy decisions at the moment.”

“I think the important thing is [to] engage in international discussions, whether they be the G7, or bilateral to the United States, or others, to come to a point where we can accept each other’s data, for example, and look at a path forwards that makes life easier and that travelers are supported if they have been vaccinated,” she said, noting that “these discussions will continue and they will evolve.”

“We are in the early days of resuming travel, and certainly in the early days of resuming travel [we’re] taking into account someone’s vaccination status, but I think every one of us will do our best at looking [at] what can be achieved in the international discussions,” she added.

Brigadier General Krista Brodie told the press conference that, as of June 17, there have been more than 35 million doses of COVID-19 vaccines delivered across Canada.

“This week’s distribution of 2.4 million doses of Pfizer-BioNTech, our weekly shipment throughout the month of June, is complete,” she said, adding that Pfizer-BioNTech adjusted its July shipment.

“They have committed to deliver the full number of doses expected for the month of July, however we now expect lower allocation in early July and larger allocation later in July to offset,” she explained.

Brodie added that projections for Moderna have “increased since last Friday’s announcement” and that instead of two shipments from “our Moderna supply arrangement, we are now receiving three shipments for a total of 8.5 million Moderna doses, a net increase of 1.5 million doses over what we announced last week.”

“We are also receiving a fourth shipment of one million doses of Moderna this week — as announced this morning — by way of the U.S. dose-sharing agreement. These doses will be available for distribution to the provinces next week,” she added, noting that over the next two weeks more than 14 million doses of COVID-19 vaccines will be distributed.

“We are working tirelessly to ensure that we can vaccinate and protect as many people as possible, as quickly as possible,” she emphasized.

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