COVID-19 vaccines have expected side-effects, but experts say they're no cause for concern

CTV National News: Vaccine allergic reaction Dr. Abdu Sharkawy says the ingredient in the vaccine that's causing allergic reactions is already widely distributed in other products.

TORONTO — As the rollout of COVID-19 vaccines approaches, one question many have is: ‘What will I feel like after I take a vaccine?’

Luckily, there are thousands of people who already know firsthand what side-effects can be expected from these vaccines: those who have already participated in clinical trials.

The first Canadians may receive a COVID-19 vaccine by next week, with 249,000 doses of the Pfizer-BioNTech shot expected by the end of this year.

The vaccine is safe, and any side-effects that appeared in trials were temporary.

But vaccine study volunteers like nurse Kristen Choi say people preparing for COVID-19 vaccinations need to know what side-effects could happen -- not to scare them away, but to let them know of what to expect when they do get the vaccine, and reassure them that it’s going to be alright.

She wrote about taking part in a Pfizer trial in the summer, in a JAMA article published this week called “A Nursing Researcher’s Experience in a COVID-19 Vaccine Trial.”

“Volunteering for the trial felt like an honourable thing to do -- and the 50 per cent chance to be randomized to the vaccine early seemed equally compelling to me as a practicing nurse,” she wrote in the paper.

She passed the necessary screening, and was soon set up to be one of the trial participants. The trial involved injecting half of the participants with a placebo, and half of them with the experimental vaccine, in order to measure whether the vaccine actually had an effect.

After the first shot, Choi felt fine, and had no idea whether she’d received the placebo or the vaccine. Her second shot, administered the following month, was a different story.

The injection site was much more painful than when she received the first shot, and by the end of the day, she “felt light-headed, chilled, nauseous, and had a splitting headache.”

She fell asleep, but then woke up at midnight, feeling even worse. She was feverish and could barely lift her arm, according to her description on JAMA.

At 5:30 a.m., she woke once again and took her temperature, finding it was a scorching 40.5 degrees Celsius.

“When I saw that I had a high fever, that's the highest fever I can ever remember having,” Choi told CTV News, “I think my initial, just gut reaction was, ‘Do I have COVID somehow?’”

She reported her reaction to the researchers at 9 a.m. when the office opened, and was told that “a lot of people have reactions after the second injection,” and that she should keep monitoring her symptoms.

Both Pfizer and Moderna say their vaccines can induce side-effects similar to the symptoms of COVID-19 infection, including fatigue, chills, headaches, muscle aches and joint pain.

In the case of the Pfizer vaccine, those older than 56 years of age experienced milder side-effects than the younger cohort of 18 to 55 years. The most common side-effects were fatigue and headaches for all ages, with as many as 60 per cent of the younger group experiencing fatigue after their second shot. Only 16 per cent of the younger group had a fever after their second shot, compared to 11 per cent of the older group, according to a briefing document submitted to the FDA.

Choi’s fever was high enough to be deemed “severe” -- which was only experienced by 0.8 per cent of participants after their second dose.

While Choi’s instinctive fear after becoming feverish was understandable, neither vaccine can give recipients the virus.

“You cannot possibly get COVID-19 from the COVID-19 vaccine,” Dr. Paul Offit told CTV News. Offit is a pediatrician specializing in infectious diseases, and an expert in virology and vaccine development who currently serves on the FDA committee overseeing and evaluating COVID-19 vaccines.

The side-effects of the vaccines may sound frightening and unpleasant, but they’re nothing to be worried about in the long run, according to experts like Dr. Sumon Chakrabarti, an infectious disease specialist.

“These are actually indicators that your immune system is activated, and not evidence of vaccine causing the disease in you,” Chakrabarti explained to CTV News. “And this is no different with the new vaccines.”

“It could cause you to feel badly enough to miss a day of work, it's possible,” Offit said. “I think people should think about these as just your immune response doing what it normally does. When you're infected with a virus or bacteria, or when you are inoculated with a vaccine, your immune response goes in action. It makes a variety of proteins called cytokines, which cause these kinds of symptoms that shift your immune system in action.”

Chakrabarti added that it’s important for people to know that these symptoms are common, but temporary, and also that they “don’t have any long-term negative consequences.”

Choi may have had an upsetting day after receiving her second shot, but it was over as quickly as it arrived.

“By the next morning, all my symptoms were gone except a sore, swollen bump at the injection site,” she wrote in her paper.

She noted that while her symptoms were common for trial participants, most participants did not have all of the symptoms she experienced at once.

Four volunteers who got the Pfizer vaccine developed Bell’s Palsy, a muscular weakness in the face, but the company says they made a full recovery.

Still, reports like these can make people hesitant about taking vaccines themselves. That’s why doctors say full transparency is critical.

“I think you would do better to explain to them that this well might happen in advance, so that they're not scared,” Offit said.

Choi agrees.

“I think that hearing about high rates of side-effects it could be something that makes people worried about the vaccine or even deters them getting it,” she said.

“It’s really important that people get both doses, for it to be effective, and so if people were to stop after the first dose [because] they didn't feel good, that could be a problem for getting the vaccine out to people.”

Any vaccines that reach the public will have gone through numerous trials spanning thousands of people in order to test the safety and efficacy of the vaccine, and then will also have to be cleared by Health Canada before Canadians start getting any injections.

And although Choi had a rougher vaccine experience than many others will have, she has no regrets in participating in the vaccine trials.

“If I had to do it over again, I absolutely would,” she said. “And I would encourage all of the health care workers and members of the public to do the same.”

Now, she just wants to prepare others for vaccination.

“Some people may need a day or two off after the vaccine to recover,” she suggested.

“I think it's important for health care workers, public health professionals, doctors, nurses, pharmacists -- anyone who might be involved in offering this vaccine to people -- to tell people up front about the potential side-effects and to explain why they're happening,” she said.

“That's how vaccines work and how our bodies learn how to protect themselves. And I think that we don't always do a good job of explaining that to people in detail.”

The concept of side-effects is daunting, but they’re far better than getting sick from COVID-19, Offit pointed out.

“This virus actually causes inflammation of your blood vessels, and because every organ in your body has a blood supply, every organ can be affected,” he said. “It can cause strokes, heart attacks, liver disease, kidney disease.

“Coronavirus does a number of things that would have never been anticipated. I think you should fear this virus, and if you have a day or two of these mild symptoms, of fever, fatigue or headaches [from taking a vaccine], that is a very small price to pay for knowing that you're going to be immune to [COVID-19].”

Offit added that he “can't wait to get this vaccine.

“And yes, I'd be more than happy to give it to my family,” he said.

Governments and vaccine makers will also continue to monitor these vaccines as millions more get the shot in the coming weeks, ensuring that a safe rollout is possible.