COVID-19 vaccine's protection against virus outweighs potential allergy risk, expert says

Health Canada on Saturday advised people with allergies to any of the ingredients in the Pfizer-BioNTech COVID-19 vaccine not to get it, but one doctor said the news shouldn't discourage those who are eligible from getting inoculated.

"I don't think Canadians should be too worried," Dr. Zain Chagla,an infectious disease physician and associate professor of medicine at McMaster University in Hamilton, told CBC News on Saturday.

The announcement from Health Canadacomes after two people in the U.K. had severe allergic reactions to thePfizer-BioNTechvaccine. The agencysaidboth individualsrecovered and had histories of severe allergic reactions.

Health Canada said it is monitoring the situation with British health authorities and the vaccine's manufacturer, and will take any new action if more issues come up.

• Read the vaccine's ingredients here, and see the full listat the bottom of this story.

Chagla said the likelihood of an allergic reaction is "not common at all," but commended health authorities on being transparent about the risk and sharing the components of the vaccine that could trigger a reaction.

"You do have to communicate out that there may be risks, and rightfully so, and also communicate about the magnitude of that risk and get people to really understand what that means," he said. "The risk of an allergy happeningis probably beyond winning the lottery that's not to say it'snot going to happen, but it's something we need to watch for, it's something we're equipped for."

'COVID-19 is not a benign diagnosis'

The Pfizer-BioNTech vaccine is the only COVID-19 vaccine approved for use so far by Health Canada, although the federal government has also ordered millions of doses of other manufacturers' vaccines. Canada's mass inoculation campaign is expected to begin in a few days.

Chagla also stressed that health officials will be monitoring for other reactions to COVID-19 vaccines that may show up over time. He said communication and transparency are the best ways to assuage vaccine hesitancy as well as clearly stating to those who are eligible the risks of not getting the vaccine.

"COVID-19 is not a benign diagnosis," Chagla said. "As much as people fixate on the adverse reactions which are rarethere is an adverse effect ofgetting COVID-19."

Britain began its inoculation program earlier this week. After the reports of the allergic reactions, the country's medicine regulator advised that anyone with a history of anaphylaxis to a medicine or food should not get the Pfizer-BioNTech vaccine.

WATCH |U.K. warns those with severe allergies should avoid COVID-19 vaccine for now:

U.K. warns those with severe allergies should avoid COVID-19 vaccine for now

4 years ago

Duration 3:23

The Pfizer-BioNTech COVID-19 vaccine caused an allergic reaction in two health-care workers in the U.K. prompting warnings from health officials there for people with severe allergies to hold off taking the vaccine.

In the U.S., topFood and Drug Administration (FDA) regulators said on Saturday that only people who have previously had severe allergic reactions to vaccines or ingredients in the Pfizer-BioNTechvaccine should avoid getting the shot. But, they saidmost Americans with allergies should be safe to receive this particular vaccine.

"We're telling people that unless they've had a severe allergic reaction to the vaccine, or one of its components, they can receive it," Dr. Peter Marks, director of the FDA division that authorized the vaccine, said at a press conference.

Pfizer executives said on Friday that there had been no cases of severe allergic reactions to the vaccine during its nearly 44,000 volunteer late-stage clinical trial. That trial excluded people with a history of severe allergic reactions to any vaccine or to the Pfizer-BioNTech vaccine's ingredients.

They said there were no anaphylactic episodes related to the vaccine in the trial, which did include about 6,000 participants respectively in both the vaccine and placebo groups with a range of allergic conditions such as pollen allergies and food allergies. Those participants had a history of symptoms including anaphylaxis.

The following are the ingredients in the Pfizer-BioNTech vaccine:

Medicinal ingredient:

• mRNA.

Non-medicinal ingredients:

• ALC-0315 = ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate).
• ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide.
• 1,2-Distearoyl-sn-glycero-3-phosphocholine.
• Cholesterol.
• Dibasic sodium phosphate dihydrate.
• Monobasic potassium phosphate.
• Potassium chloride.
• Sodium chloride.
• Sucrose.
• Water for injection.