It’s been a bumpy road for one of the leading COVID-19 vaccines.
On Monday, Canadian officials became the latest to reconsider rollout of the AstraZeneca vaccine in certain age groups. The decision marks another setback for a dose that has faced scrutiny over everything from trial protocol to efficacy data.
The National Advisory Committee on Immunization, which provides guidance for the country, updated its advice, and is now recommending the shot not be given to those under the age of 55, while its potential link to blood clots is investigated further.
This follows weeks of questions in Europe about what connection the dose might have to blood clots that a small number of recipients have experienced.
Multiple provinces, including Ontario, Alberta, Prince Edward Island and Quebec, have now paused rollout of their doses.
About a dozen European countries, including France, Germany, Spain and Italy, paused their use of the vaccine pending an investigation by their regulator. Many resumed last week after the European Medicines Agency said its preliminary review found that the vaccine was not associated with a higher risk of blood clots, though its investigation continues.
But a recent scientific article that has yet to be reviewed described the first nine cases that occurred in Germany and Austria, all of them in young people.
Dr. Zain Chagla, an infectious diseases physician and associate professor at McMaster University, called the NACI decision “reasonable,” given the current supply of other vaccines, as it will buy scientists time to figure out exact what’s going on. He adds that the benefits still clearly outweigh the risks for anyone over 55, though he says the repeated course changes could fuel anti-vaccine sentiment.
Developed by a British-Swedish pharmaceutical company in partnership with Oxford University, the vaccine, cheap and easy to transport, was expected to be a gamechanger for poorer, hard-to-access regions around the world.
But it’s come under scrutiny multiple times, leaving lingering questions about its efficacy and, Chagla worries, a dent in public trust.
“It’s tough. I think when you have this many strikes against you, some of them are your own but some of them are biologic issues like this side-effect, or the issues with the South African variant, it’s hard to come back from all of that.”
Here are some of the stumbles in the vaccine’s rollout so far.
Wrong dose given in trials
The first major confusion came in November with a news release from the company announcing that the vaccine was as much as 90 per cent efficacious, based on a trial in which the company had tried out two different dosages.
“Excitingly, we’ve found that one of our dosing regimens may be around 90 per cent effective and if this dosing regime is used, more people could be vaccinated with planned vaccine supply,” Oxford professor Andrew Pollard said in a release.
But within days company officials acknowledged that one of the dosages — the one that appeared to yield more protection — was actually given by mistake, meaning only a relatively small number of people were tested.
That admission, combined with what some experts said were other data irregularities, undercut some public confidence in the vaccine.
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Use in seniors
The United Kingdom was the first nation to authorize the dose for emergency use in late December, but the vaccine quickly faced criticism about the relative lack of seniors in its human trials, prompting questions about whether it worked in older adults.
While the European Union’s regulator greenlit the dose in late January, several European countries declined to give it to those over 65, with French President Emmanuel Macron sparking headlines when he called early results “not encouraging.”
But in time, real-world evidence prompted most countries to reverse the decision, and give the dose to all ages.
Canada approved the vaccine here in late February, but the national committee tasked with providing vaccine advice initially recommended that it not be given to seniors, a move that sent the provinces scrambling to make their own policies. That decision was reversed less than a month later.
South African variant
In February, South Africa paused rollout of the dose after some early evidence suggested the vaccine was less effective against the virus variant that had emerged in that country. The World Health Organization, however, continued to recommend the shot be used, arguing that slightly reduced protection was better than none.
The result has been real confusion. Some health workers in Europe have reportedly declined to take the vaccine over efficacy concerns, leaving Germany and France reportedly stuck with thousands of unused doses, according to Forbes.
Similar trepidation has been reported in some places in Canada. According to CTV, the Montreal North health authority reported that eight per cent of people declined the shot on Saturday once they found they were set to receive an AstraZeneca shot.
Allegedly cherry-picking data
Last week, AstraZeneca put out a news release about early results from its U.S. trial, which looked at results from more than 30,000 people and found that the dose was 79 per cent effective, according to the release.
The company had been criticized for not including enough seniors in earlier trials; an omission researchers had worked to correct this time, with the same release pointing out its shot was even slightly more effective in those over age 65.
But a day later, the American National Institute of Allergy and Infectious Diseases posted its own short statement online, saying that the Data and Safety Monitoring Board — a panel of experts that keeps an eye on ongoing trials — had “expressed concern” that AstraZeneca had used outdated information, providing an “incomplete” view of the study.
The British-Swedish multinational then fired back with another release, saying the story had been based on an early look at results, based on a cut-off date of Feb. 17, and that more information would be coming soon. (Another primary analysis released two days later found the shot was 76 per cent efficacious.)
The fact that this played out publicly was very unusual, Chagla said at the time.
“I don’t think I’ve ever seen a (Data Safety and Monitoring Board) make a public announcement like this, other than stopping a trial and saying it’s not working,” he said.
With files from The Canadian Press
Alex Boyd is a Calgary-based reporter for the Star. Follow her on Twitter: @alex_n_boyd
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