A front-running team in the race to develop a COVID-19 vaccine has put its late-stage trial on hold after a reported “unexplained illness” in one of the trial volunteers. Here’s what that means for the quick development of a COVID-19 vaccine.
What kind of vaccine trial got put on hold?
The trial was a Phase 3 clinical trial for a vaccine being developed by the University of Oxford and pharmaceutical company AstraZeneca.
It’s the largest type of clinical trial, requiring thousands of volunteers, and is the last of three stages of human testing before a vaccine can be approved for use. Its main goals are to:
Test the efficacy of the vaccine at preventing the disease compared with a placebo
Get a better idea of possible side effects and how often they happen, including rare side effects that might not show up in smaller trials.
The company is running Phase 3 trials involving thousands of people in the United Kingdom and smaller numbers of people in Brazil and South Africa. It is also recruiting 30,000 people in the United States for its largest study.
The vaccine being tested is a non-replicating viral vector vaccine.
The federal government reported on Aug. 31 that it was close to a deal to secure doses of this particular vaccine for Canadians.
Why was the trial suspended?
AstraZeneca reported Tuesday evening that there was a “potentially unexplained illness” in one of its trials in the U.K.
That triggered a “standard review process,” intended to ensure safety when that happens.
While the trial is suspended, the incident will be investigated by independent reviewers not involved in the trial itself.
What kind of illness was it?
AstraZeneca said Wednesday that the patient had neurological symptoms associated with a spinal inflammatory disorder called transverse myelitis, but a final diagnosis was still pending as more tests are carried out, Reuters reported.
That involves localized inflammation of the spinal cord, which can cause symptoms such as weakness, loss of sensation or even paralysis of the arms and legs. It can be caused by autoimmune diseases, viral, bacterial or fungal infections or parasites, but it has also been reported as potentially a rare side effect of vaccinations for diseases such as influenza or rubella.
However, researchers who have studied it note that it’s difficult to confirm or exclude the link between the disease and vaccination, since it can occur coincidentally due to other causes after vaccination.
WATCH | Infectious disease specialist explains suspension of trial:
Dr. Sumon Chakrabarti, infectious diseases specialist at Trillium Health Partners, said safety is paramount in vaccine clinical trials, and temporary suspensions are not unusual to evaluate any unexplained illness in a participant. 4:31
What is the goal of the review?
It will try to determine whether the illness was related to the vaccine.
Because trials like this are typically double-blinded, the researchers don’t know whether a given volunteer received the vaccine or a placebo. That’s one of the reasons why the review needs to be conducted by an independent committee that is not doing other analyses in the study.
Even if the volunteer received the vaccine, the timing of the illness could still be coincidental and unrelated to the vaccine.
Dr. Sumon Chakrabarti, an infectious disease specialist at Trillium Health Partners in Toronto, told CBC News Network that if the patient does have transverse myelitis, he or she will likely be tested for different types of infections to see if a cause can be determined.
“I’ve seen many of these cases myself, and we often come up with viral causes,” he said.
If that happens, the review may be able to rule out the vaccine as the cause and allow the trial to resume.
AstraZeneca’s halt to a big coronavirus vaccine trial is a cause for concern, says Toronto respirologist Dr. Samir Gupta, who also hailed B.C.’s transparency around growing coronavirus cases. 0:50
How often do pauses like this happen?
On the one hand, they’re not triggered by “mild” side effects, and there haven’t been any publicized for any COVID-19 vaccine trials so far, despite the large number underway. However, AstraZeneca disclosed Wednesday that it had briefly paused a COVID-19 vaccine trial in July after a study volunteer was found to have multiple sclerosis. An independent review panel concluded the illness was not related to the vaccine.
Dr. Samir Gupta, associate professor of medicine at the University of Toronto, said that “it’s not a routine thing to stop a massive trial mid-course like this.”
But on the other hand, it’s not unexpected, given the size of the trial, said Dr. Michael Gardam, an infectious disease specialist at Women’s College Hospital in Toronto.
“I would argue for probably every vaccine that’s ever come to market, there’s been an event like this,” Gardam said.
“When you’re giving vaccine to tens of thousands of people, something’s going to happen to one of them. And chances are it’s happenstance … it’s not linked to the vaccine. But each time, you have to investigate it.”
WATCH | How COVID-19 vaccines are being created quickly and safely:
Some potential COVID-19 vaccines are already in the third stage of clinical trials. It’s taken a lot of effort and money to squeeze a process that can normally take five years into about 10 months and still be done safely. 2:17
Will the pause slow down development of a vaccine?
Gardam said he doesn’t think it will cause a significant delay.
Investigators will try to figure out “a reasonable explanation” for the cause of the illness, Gardam said, which may take some time.
A pause occurred during the Phase 1 trial of a Canadian-made Ebola vaccine in 2014 after several volunteers reported joint pain. An investigation found that the side effect was likely caused by the vaccine, and the study resumed three weeks later with a lower dose.
In this case, Gardam said he thinks it will be hard to draw any conclusion based on one illness and that the University of Oxford researchers will be able to “quite quickly get back up and running again.”
However, they will need to collect more data to see if others show similar illnesses. If that happens, he said, “then that’s a completely different story.”
WATCH | When will a COVID-19 vaccine be ready?:
An infectious disease specialist answers viewer questions about a COVID-19 vaccine including what stage vaccine development is in and when the public could expect one to be ready. 2:58
How worried should we be about this pause?
If it turns out that this is a potential adverse effect of this vaccine, “that would obviously be a substantial showstopper for this vaccine,” said Dr. Andrew Morris, an infectious disease specialist at Sinai Health, the University Health Network and the University of Toronto.
He’s concerned there wouldn’t be access to the vaccine, which is in advanced stages of development. It’s also one that many countries are pinning their hopes on, with substantial investment and three billion doses reserved by governments around the world and by the COVAX Facility, which aims to provide access to more than 70 per cent of the world’s population.
Morris said he’s also concerned that the media coverage will discourage people from enrolling in vaccine studies or increase anti-vaccination hype.
“Any step back is really a setback for all of us,” he said.
But at the same time, researchers such as Gardam say in some ways, the pause should ease people’s concerns, as it shows that the system is working and highlights the importance of Phase 3 clinical trials to ensure the safety of vaccines.
“This in and of itself isn’t a big deal,” he said. “This is what is supposed to happen…. This gives me some comfort.
“The fact that this has been stopped appropriately, it’ll be investigated. We’ll learn about it and then presumably the trial will start up again. That’s exactly what’s supposed to happen.”
Netflix on Thursday reported that its subscriber growth slowed dramatically during the summer, a sign the huge gains from the video-streaming service’s crackdown on freeloading viewers is tapering off.
The 5.1 million subscribers that Netflix added during the July-September period represented a 42% decline from the total gained during the same time last year. Even so, the company’s revenue and profit rose at a faster pace than analysts had projected, according to FactSet Research.
Netflix ended September with 282.7 million worldwide subscribers — far more than any other streaming service.
The Los Gatos, California, company earned $2.36 billion, or $5.40 per share, a 41% increase from the same time last year. Revenue climbed 15% from a year ago to $9.82 billion. Netflix management predicted the company’s revenue will rise at the same 15% year-over-year pace during the October-December period, slightly than better than analysts have been expecting.
The strong financial performance in the past quarter coupled with the upbeat forecast eclipsed any worries about slowing subscriber growth. Netflix’s stock price surged nearly 4% in extended trading after the numbers came out, building upon a more than 40% increase in the company’s shares so far this year.
The past quarter’s subscriber gains were the lowest posted in any three-month period since the beginning of last year. That drop-off indicates Netflix is shifting to a new phase after reaping the benefits from a ban on the once-rampant practice of sharing account passwords that enabled an estimated 100 million people watch its popular service without paying for it.
The crackdown, triggered by a rare loss of subscribers coming out of the pandemic in 2022, helped Netflix add 57 million subscribers from June 2022 through this June — an average of more than 7 million per quarter, while many of its industry rivals have been struggling as households curbed their discretionary spending.
Netflix’s gains also were propelled by a low-priced version of its service that included commercials for the first time in its history. The company still is only getting a small fraction of its revenue from the 2-year-old advertising push, but Netflix is intensifying its focus on that segment of its business to help boost its profits.
In a letter to shareholder, Netflix reiterated previous cautionary notes about its expansion into advertising, though the low-priced option including commercials has become its fastest growing segment.
“We have much more work to do improving our offering for advertisers, which will be a priority over the next few years,” Netflix management wrote in the letter.
As part of its evolution, Netflix has been increasingly supplementing its lineup of scripted TV series and movies with live programming, such as a Labor Day spectacle featuring renowned glutton Joey Chestnut setting a world record for gorging on hot dogs in a showdown with his longtime nemesis Takeru Kobayashi.
Netflix will be trying to attract more viewer during the current quarter with a Nov. 15 fight pitting former heavyweight champion Mike Tyson against Jake Paul, a YouTube sensation turned boxer, and two National Football League games on Christmas Day.
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