Still worried about getting a vaccine for COVID-19? Here's how to understand the rare, but real, risks

Whether you're scrolling through your Facebook feed, checking texts from friends and family, or chatting with fellow parents from your kid's hockey team, you're bound to encounter questions about whether or not it's safe to get vaccinated.

Billions of people around the world have signed on to get their shots to ward off COVID-19. But millions of others are waiting and wondering.

Are these vaccines safe? Do they cause major side effects? What are the long-term health impacts? Can they kill you?

The questions, to some degree, make sense. No drug is risk-free. And there are some known, headline-making adverse reactions following COVID-19 vaccines, including rare cases where people have died.

There's also plenty of misinformation circulating, from debunked studies on vaccination risks to anecdotal, unproven accounts of negative outcomes after a shot.

Yet there's also overwhelming evidence that these vaccines are saving countless lives while carrying far, far lower risks than the disease they're designed to prevent one that has so far killed close to five million people around the world.

So why does it sometimes feel like concerns about vaccines are taking up rent-free space in so many people's brains?

Dr. Esther Choo, a professor at the Oregon Health and Science University in Portland, Ore., puts it this way: If you hear a scary story about someone's vaccination experience, whether it proves true or not, it typically "counts more" on an emotional level than any reassuring safety statistic.

That means navigating fraught discussions around vaccination requires taking a step back to evaluate all the evidence beyond the anecdotes.

"The known threat looms larger in your brain than the numbers that people may bring up to you," she said. "Our brains are just so consumed by COVID."

Adverse event reports remain rare

Our emotional reactions to negative vaccinationstories, whether they're misinformation or accurate instances of adverse reactions, can feel a bit like our response to airplane crashes.

All the evidence shows that your risk of dying in a plane crash is extremely low, particularly when you compare it to getting behind the wheel of a car. But spotting one headline about a rare-but-tragic air accident might bring up fears that no amount of data can sway.

"There are lots of studies that show that, as humans, we do a really bad job at assessing statistics and relative risk when it comes to things that impact us," said Matthew Miller, an infectious diseases researcher at McMaster University in Hamilton.

"It's the same reason why people feel, in general, that they are more likely to win the lottery than someone else, despite the fact that the chances are extremely small and the odds of them winning, versus someone else winning, are exactly the same."

So what do we actually know about the risk profile of leading COVID-19 vaccines?

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Researcher explains how vaccine safety is studied, monitored

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McMaster University vaccine expert and infectious diseases researcher Matthew Miller explains how vaccines are developed to ensure they're safe for public use, and why they're important to monitor for any safety signals long after clinical trials end.

For starters, there's a massive body of data available to gauge how safe these shots are. But knowing how to navigate it can be tricky.

Globally, more than 6.2 billion vaccine doses have been administered to date, according to World Health Organization figures, and researchers in various countrieshave been tracking potential adverse reactions whilevaccinations have ramped up.

In Canada, that includes the Canadian Adverse Events Following Immunization Surveillance System (CAEFISS) and Canada Vigilance Program, which both allow people to report health issues post-vaccination which might be linked to the vaccine.

So far, there have been more than 17,000 reports of adverse events post-vaccination in Canada, totalling just 0.031 per cent of all doses administered.And there could even be fewer actual events than that already-low tally suggests.

Vaccination-reporting systems can be a major source of confusion for the general public, Miller explained, because they're a bit of a free-for-all.

"Those systems are really meant to sort of catch anything and everything that could possibly be associated with a vaccineeven things that are highly improbable," he said.

"A lot of data is collected on things that have nothing to do with the vaccine. So, for example, let's imagine that an individual with a history and high risk of stroke gets a vaccine. And then, two weeks later, has a stroke. In the vast majority of cases, the stroke had nothing to do with the vaccine."

Canada monitoring 3 'early signals' of health issues

All reports of adverse events following immunization are included in the government's reporting, "regardless of whether they have been linked to the vaccines," confirms the federal government's vaccine side effects website.

"This is because we need to look at all the data available to us so we can detect any early signals of an issue."

That means while many reports likely have no connection to a vaccine, other trends can emerge, showing possible connections between getting a shot and developing certain health issues.

Currently, Canada is monitoring three safety signals: reports ofGuillain-Barr Syndrome (GBS), myocarditis and a rare but serious form of blood clotting.

In the case of GBS, anautoimmune disorder in which a person's own immune system damages their nerves, Canadian data indicates a higher number of cases than would normally be expected in the general population.

As for myocarditis,acondition involvinginflammation of the heart muscle,it typically impacts younger males, and is now being linked to mRNA-based vaccines like those made by Pfizer-BioNTech and Moderna.

One study from Israel published in the New England Journal of Medicine showed a slight increased risk of myocarditis after vaccination but the researchers stressed that COVID-19 is more likely to cause the condition than the shot.

Other early studies, including a not-yet-peer-reviewed preprint paper published on Thursday, are also showing that people typically experience a smooth recovery and prompt cardiac-function improvement if they do develop myocarditis post-vaccination.

WATCH |Benefits of COVID-19 vaccine outweigh low risk of heart inflammation, experts say:

Benefits of COVID-19 vaccine outweigh low risk of heart inflammation, experts say

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A small number of cases of heart inflammation specifically, myocarditis and pericarditis have occurred in teens and young adults following mRNA COVID-19 vaccination, but experts say the benefits of a vaccine far outweigh the risk.

"Most of these people are treated for a couple of days with standard, over-the-counter anti-inflammatories," said Miller.

"They don't require steroid treatments or prolonged hospital stays. And there's no evidence to suggest that those sort of acute [myocarditis] flares cause any sorts of long-term damage."

"It seems to be a very rare side effect and one that is usually very mild," echoed Dr. Christopher Labos, a Montreal-based cardiologist. "So not, generally speaking, something that should dissuade somebody from getting vaccinated."

A different blood-clotting condition marked by low platelet levels, which has been linked to the AstraZeneca-Oxford and Johnson & Johnson COVID-19 vaccines, has proven more serious.

In Canada, as of Oct.1,federal data shows there have been six confirmed post-vaccination deaths involving this rare form of blood clot though it's unclear how many of thosemight have been vaccine-induced.

"Investigations into causality are ongoing for these deaths," said a spokesperson forHealth Canada and the Public Health Agency of Canada in an emailed response to an inquiry from CBC News.

For those worried about longer-term health impacts, Miller stressed those kinds of post-vaccination issues are historically very rare, and far more likely with other drugs used on a regular basis for months or years on end.

"The vaccine is a drug akin to a pill or any other one-time injection we get, where the drug is removed from our system very quickly," he said.

For the small number of people who do wind up having vaccine-related health issues, the government does have a vaccine injury support program that provides funding.

"You could be one of the unlucky few, in the case of these vaccines, who develops one of these severe adverse events," said Angela Rasmussen, a virologist with the University of Saskatchewan's Vaccine and Infectious Disease Organization.

"But what you should also understand specifically about the COVID-19 vaccines is that these adverse outcomes are extremely rare."

Post-vaccine deaths 'not necessarily related' to the shot

Canadian data shows there have been 194 adverse-event reports in total where someone wound up dying following a COVID-19 vaccination out of a whopping 55 million doses that have been administered in the country to date.

Seventy-four of those deaths were unlikely caused by the vaccine, 70 could not be assessed due to "insufficient information," while 44 remain under investigation.

"Although these deaths occurred after being vaccinated with a COVID-19 vaccine, they are not necessarily related to the vaccine," reads that federal website.

Outside medical experts say it's important to keep those numbers in context, given how many vaccines have been safely administered in Canada and how the handful of confirmed vaccine-related deaths compares to the massive death toll from COVID-19 itself.

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Canadians aged 12 to 39 now have the lowest vaccination rates in the country. And with the majority of COVID-19 cases appearing in unvaccinated people, experts say its as important as ever to increase vaccination rates across Canada. So how can you use science to counter the misinformation behind vaccine refusal?

Roughly 28,000Canadians have died while infected with the coronavirus since the pandemic began.There's also a growing body of evidence showing that Canada's approved vaccines offer much higher protection against that kind of dire outcome, while unvaccinated individuals make up the bulk of serious infections.

"By not getting the shot, to a certain degree, you're actually choosing to put yourself at higher risk for getting COVID," Rasmussen said. "And, you know, everything is a choice, including not doing anything. That's a choice, too."

But making that choice, for some Canadians, can still feel overwhelming. The barrage of numbers, the hearsay, the rampant online misinformation it's all tough to parse.

"These are really high-anxiety times. It seems everywhere you go, there's something scary:It's scary to get the infection. It's scary to get a medication you're not familiar with," said Choo.

But based on her lived experience, shesays getting a shot remains the safest option.

"When you see COVID day in, day out, and it's overwhelming our hospitals and none of you can think of a case you've treated of severe vaccine side effects you have this perspective on it."