COVID-19 vaccines: Will Pfizer and Moderna have side effects like AstraZeneca in the long-term?

·3-min read

The recent decision by five Canadian provinces to change the way they administer the AstraZeneca vaccine should not deter anyone from getting vaccinated, or to regret getting AstraZeneca if they already did, one expert says.

Samantha Yammine, a neuroscientist and science communicator, says that with more than a billion vaccines already given out worldwide, it’s highly unlikely that we’ll see any major, common issues develop with other vaccines now.

“The comforting thing is that there have been millions of doses of the mRNA vaccines given out, so at this point it’s unlikely anything new would come up that would affect a lot of people,” she said. “If anything new comes up at this point, it would be astronomically rare.”

While the blood-clotting condition caused by AstraZeneca is concerning, Yammine says there isn’t a lot of unpredictability surrounding vaccines, and the benefits of receiving them far outweighs any potential risks.

“Vaccines are among the most well-studied medicines. We have got to keep all of that in mind, and remember how many people have died of COVID-19. We’re going to see that any place that has had a lot of vaccinations given out has also seen a significant decrease in their COVID cases. All of that has to be kept in perspective.”

Why do people doubt COVID-19 vaccines?

A lot of the hesitancy encompassing vaccines comes from a poor understanding of how the medicines actually work, Yammine says. And with over a billion doses administered worldwide, and more than a year’s time, most of the impacts of the vaccine have already been identified.

“The vaccines themselves, the product in the vaccines, only stays in your body for a very short amount of time. So any issue that the vaccine products themselves could have show up rather quickly. Even in the case of VITT (vaccine-induced thrombotic thrombocytopenia), you’re seeing the effects happen within a month window. So we’ve observed all of the vaccine related issues that we could because now the vaccines have been given out for over a year,” she said.

“The immune protection from the vaccines, that’s what’s long-lasting.”

Yammine also attributes some of the hesitation around vaccines to the way our brains are wired when it comes to thinking about risks vs. rewards. Most medicines we take cure us of whatever’s making us sick, or offer some form of instant pain relief. Vaccines, however, are preventative medicines, so if they’re working correctly, which they predominantly are, the reward is that you don’t get sick.

“Vaccines are a victim of their own success because when they work, nothing happens. And that’s not that interesting of a news story, and it’s not something we’ll notice in our day to day. So that’s why people feel weird about vaccines.”

B.C. and New Brunswick are the latest provinces to announce they would stop offering first doses of the AstraZeneca vaccine, following closely on the heels of Alberta, Ontario and Quebec.

The vaccine has been linked to a blood clot disorder, and though it is rare, researchers found it affects roughly one in every 26,000 cases to one in every 127,000.