Don't Panic Over Vaccine Blood Clots. The System Is Working

Blood clots following AstraZeneca and Johnson & Johnson doses have sparked fear. But experts say vaccines are safe—and those in charge are working hard to keep it that way.
COVID-19 vaccination; Pfizer vaccine
COVID-19 vaccine campaigns are ramping up around the world, with rollouts varying from country to country. (Photo by Jeff J Mitchell - Pool /Getty Images)

As vaccination campaigns speed up around the world, it’s becoming increasingly difficult to keep up with news detailing the risks and effectiveness of different vaccines. And with that firehose of information comes a concern: that constantly changing public health information may lead to vaccine hesitancy.

Recently, several countries, including Canada, Denmark, the U.S., and Austria, have reported cases of (extremely rare) blood clots following AstraZeneca and Johnson & Johnson doses. Most have affected younger women. In response, the U.S. suspended the use of Johnson & Johnson, while the company delayed its rollout in Europe. 


AstraZeneca’s rollout now varies from country to country. Many have restricted eligibility based on age, with Britain, for example, saying people under 30 shouldn’t get it. Meanwhile, Denmark has done away with AstraZeneca altogether. The U.S. still hasn’t approved it. Canada initially prohibited the vaccine for people under 55 before walking back the directive on Wednesday. 

"Health Canada still considers the benefits of the AstraZeneca vaccine to outweigh the risks of getting COVID-19," said Dr. Supriya Sharma, the chief medical adviser at Health Canada who manages the regulation of the COVID-19 vaccines. “We are not limiting the use of the vaccine to any specific age group or sex."

According to estimates so far, the risk of suffering a blood clot from AstraZeneca is about 1 in 100,000 or 1 in 250,000, Sharma said. (The risk of getting a blood clot from COVID-19 is up to 10 times higher.) Preliminary data out of the U.S. suggests that blood clot risks are about 1 in a million for Johnson & Johnson. “Six cases of blood clots in combination with low platelets have been reported in the U.S., out of more than 6.8 million doses administered. All six cases were in women aged between 18 and 48, with symptoms occurring six to 13 days after vaccination,” wrote the British Medical Journal.

Yet Twitter is aflame with some people saying they’d rather wait for Pfizer or Moderna—which could also result in blood clots, it turns out—while others are pleading with people to take whatever jab they can get. 


“People are debating their preference about one vaccine over the other as if they're choosing a pair of designer shoes. It’s very frustrating,” said Dr. Katrina Plamondon, University of British Columbia Okanagan’s nursing school professor and global health specialist.

VICE World News spoke with three experts, all of whom said the approved COVID-19 vaccines are safe. “Denmark won’t use AstraZeneca at all because they've had cases there and estimated the risk was worse than 1 in 100,000,” University of British Columbia epidemiologist Dr. Stephen Hoption Cann said. “It’s still a very rare adverse effect and a person is much more likely to develop (blood clots) by other things—like smoking or oral contraceptives or even just getting pregnant.”

Confusing rollouts are proof the system is working

While the approved vaccines are safe, building trust in vaccines, so that people feel safe, is more complicated. Dr. Manish Sadarangani, director of the Vaccination Evaluation Centre at the B.C. Children’s Hospital, said nimble public health responses are a “good thing.”

“To me, that’s an indication that the systems we have in place for vaccine surveillance after they start being used are working,” Sadarangani said. “Risks are identified and being acted upon and we’re able to work in real time.”


Sadarangani acknowledged that the information can lead to uncertainty. “You can’t change policy every week because it comes across as not being sure about what you're doing,” Sadarangani said. But, he said, the risks associated with all of the approved vaccines are low, and experts are trying to analyze vaccine data rapidly, so that policies are up-to-date, accurate, and evidence-based. 

How does policy adapt to evolving information?

When credible and overwhelming evidence shows that a vaccine is unsafe for some groups, policies can shift quickly to better protect them. In theory, if a vaccine was significantly more dangerous for women, health authorities could decide to administer the vaccine to men only—but a lot of factors need to be examined before decisions like that are made, Hoption Cann said. 

When it comes to AstraZeneca and Johnson & Johnson, “we know women are at higher risk, but we don't know the details about what is the risk factor: Is it individuals who were also smokers? On oral contraceptives? We’re trying to find more detail on that,” Hoption Cann said. 

Right now, we know COVID-19 risks vastly outweigh those associated with the vaccines. “It’s important to get as many people vaccinated as possible,” Hoption Cann said, pointing to the U.K. and Israel, where mass vaccination campaigns have resulted in significant drops in new infections. 


What can we do to improve trust?

Improving trust in vaccines can start during clinical trials, long before they’re approved for wide scale use. Historically, women, people of colour, and other diverse groups have been left out of medical research, so including them can help, even if there is no reason to believe a drug or vaccine will affect diverse groups differently.

“People will ask, ‘How many people like me were in the trial?’ It's where people get reassurance,” Sadarangani said.

Back in September, U.S. chief medical officer Dr. Anthony Fauci specifically called on researchers to include low-income, Black, and brown people in trials because those communities have suffered the worst COVID-19 outcomes. 

“We need to get a diverse representation of the population in the clinical trials," Fauci said at the time. "So when (vaccines) are proven to be safe and effective, we can say they are safe and effective in everyone, not only in whites.”

But many of the hardest hit groups don’t have the time or resources (e.g. days off and transportation) to participate in trials, Hoption Cann said.

“Even with these COVID studies, researchers tried to increase diversity and went through extra efforts to do that, but we still see those minority populations being underrepresented,” Hoption Cann said. “It’s not like you can just say, ‘OK, everyone can join the trial.’ A lot of groups are left out for various reasons.”


Additionally, people of colour around the world, including Indigenous communities in Canada and Black Americans, have historically been “used and violated and abused” during medical research and drug testing, said Plamondon. “There are reasons why people might be hesitant to volunteer. There is distrust from people underrepresented—and for good reason.”

The way to improve diversity and inclusion is to fund it through campaigns, ideally in diverse languages, and meaningful outreach, Sadarangani said. But it’s hard to convince funders, including governments, to dish out extra funds. 

“Most grants, we’re asked to cut our budgets,” Sadarangani said.

Debates over vaccines brands are privileged debates

Ultimately, most people around the world don’t get to debate which vaccine they’d rather get because they either have fewer options or don’t have any options at all. 

“The majority of the world doesn't have any access to vaccines,” Plamondon said. “And the things they do have access to (AstraZeneca) are the things we’re treating as beneath us.”

VICE World News previously reported how “vaccine nationalism,” propped up by rich countries, could worsen and extend the pandemic. According to Plamondon, the latest debates show how “entitled” many of us are. “Rich countries in the global north think that they deserve a better life somehow or that our humanity matters more,” she said, adding that we should be taking whatever vaccine is offered to us, while also pushing for equitable distribution around the globe. 

At the same time, though, Plamondon said vaccine hesitancy and concerns around safety are valid, and the current news cycle can be overwhelming for people. She pointed to public health standards as a way to reassure those who are worried. 

Vaccines go through “such rigorous testing” that pauses, including Johnson & Johnson’s current vaccine delay, should be viewed as “reassuring” because it means experts are paying close attention, she said.  “We should have a lot of confidence in the thresholds used to test vaccines.” 

Follow Anya Zoledziowski on Twitter.