AstraZeneca approved for second doses
Ontario says vaccine will be available starting next week to those eligible
Ontario is giving a shot in the arm to its COVID-19 vaccination efforts by approving the AstraZeneca vaccine for second doses, starting next week with people who got their first jabs in mid-March.
As first disclosed by the Star on Wednesday, the province will go ahead with the booster shots of AstraZeneca and related Covishield vaccines despite a pause on first doses over concerns about an increased incidence of rare blood clots.
The latest evidence shows those clot risks are far more rare for second shots, making it safe to proceed with a batch of doses expiring May 31, chief medical officer Dr. David Williams said Friday.
“Getting COVID far exceeds the risk we’re talking about.”
Starting Monday, adults aged 60-64 who received their first shots March 10 to 19 at pharmacies in Toronto, Windsor-Essex and the Kingston area as part of a pilot project can make appointments by calling pharmacies.
So can a smaller number of people who got jabs during the same period at doctors’ offices in Toronto, Peel, Hamilton, Peterborough, Simcoe-Muskoka and the Wellington-DufferinGuelph health unit.
About 55,000 doses are up for grabs initially — far fewer than the number of people eligible, officials said.
While some pharmacies in the pilot project zone no longer have AstraZeneca in stock, they will be able to receive doses being collected and redistributed from drug stores around the province if they wish, or from the provincial supply, said Justin Bates of the Ontario Pharmacists Association.
“Some may put their hand up, some may not,” he told the Star.
Details on which pharmacies will have AstraZeneca or Covishield supply next week are expected to be listed on the government’s COVID-19 website Monday or Tuesday, Bates added.
“We’re doing what we can to make sure there’s no wasted doses.”
Uptake on the vaccines will be “closely monitored” to manage inventories, said Dr. Dirk Huyer, Ontario’s chief coroner who is doubling as head of the province’s outbreak response and serves on the vaccination distribution task force.
The timing means people who got their first shots mid-March will be a week or two ahead of the 12-week period at which a second dose of AstraZeneca provides peak protection against COVID, but the difference is “fairly negligible,” Williams said.
He stressed a second dose of AstraZeneca vaccine at a 10- to 11-week interval is “safe and provides strong protection against COVID-19.”
Dr. Anna Banerji, a professor at the University of Toronto medical school who also works at vaccination clinics, urged anyone eligible to get the booster.
“If it’s 10 weeks … that’s perfectly fine,” she added. “They should get the shots. There’s no point wasting those doses.”
Anyone accepting one of the early shots will be asked to provide “informed consent” on the risks, which are now one in 600,000 for a clot — an increase from one in a million on May 11 when AstraZeneca was paused — based on statistics from the United Kingdom where the vaccine is in wide use, the doctor added.
That compares to about one in 60,000 for clots following a first dose in Ontario.
Ontario has just received a fresh shipment of 254,5000 AstraZeneca vaccines and decisions will be announced soon on how to get them into arms of people who got first shots after March 19, but the province is aiming for the 12-week interval.
“We still like to go for that 12-week period if we can to make sure people get the maximum, peak effect,” Williams told a news conference.
The 12 weeks is earlier than the 16-week interval adopted in Canada for Pfizer and Moderna vaccines to ensure more people could get first doses, which in turn provides a broader level of protection from COVID-19 across the population.
With almost a million Ontarians over the age of 40 having received AstraZeneca between March 10 and the May 11 first dose pause, more shipments are expected.
However, officials are planning to offer second shots of Pfizer and Moderna vaccines, made with mRNA technology, to people who received first doses of AstraZeneca, a viral vector vaccine, should they wish to switch.
That decision is pending studies on vaccine mixing that show “early promise” and a recommendation from the National Advisory Committee on Immunization, Williams said.
AstraZeneca shots were paused almost two weeks ago after an increase in cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) in the province raised estimates of the risk of blood clots to one in 60,000 from one in 100,000 the previous week.
The decision to move ahead with second jabs of AstraZeneca was announced a day after Premier Doug Ford unveiled a three-stage plan on reopening the economy that is tied directly to vaccination rates, including second doses.
About 52 per cent of Ontarians have had at least one shot and almost four per cent are fully vaccinated.
Banerji said the government needs to step up second doses with some mass vaccination clinics having plenty of extra capacity.
“There’s no point in waiting until every person’s had a first dose,” she added, suggesting separate lines at mass clinics for first and second doses, starting with older adults.
“Let’s get the show on the road.”