CM – Allergic reactions to Pfizer, AstraZeneca COVID-19 vaccines rare, study shows


Stephanie Liu Writer


A three-month study of side effects from the vaccine found that severe allergic reactions to the Pfizer-BioNTech and AstraZeneca COVID-19 vaccines were rare, affecting less than two percent of people, while milder reactions such as tenderness and injection site pain were fairly common.

While detailed data on Moderna and Johnson & Johnson vaccines are not yet available, a peer-reviewed study published in The Lancet Infectious Diseases Journal on Tuesday analyzed the proportion of people who experienced side effects after their first and second doses of Pfizer . BioNTech vaccine; and after the first dose of the AstraZeneca vaccine. The data are based on clinical studies carried out over a period of three months.

Side effects have been found to be more common in younger people and women. Local side effects occur with both vaccines. like pain, tenderness and swelling at the injection site? were the most common type of symptoms after a person got their vaccine. Less common side effects are systemic symptoms that affect the entire body, such as chills and fever, and severe allergic reactions.

Dr. Isaac Bogoch, an infectious disease specialist at Toronto General Hospital, said he speculated that people have these symptoms because their immune systems are responding to the vaccine, which is why their reactions are not uncommon.

« The reason people get these side effects is because you’re actually getting your immune system going, » Bogoch told Thursday. « You have an immune response and your immune system is doing what it should, so people feel the way they feel. »

The study found that approximately 72% of people experienced a local side effect after the first dose; and 69% of people experienced a local side effect after their second dose.

The most common side effect after receiving the first and second doses of Pfizer vaccine is a feeling of tenderness at the injection site.

Looking at the number of reports of systemic side effects, 13.5% of people said they experienced this after the first dose and 22% of people after the second dose.

While allergic reactions are rare, the most common reaction was skin burning, but only 1.1% of people experienced it after the second dose.

In the study, almost 59% of people reported having a local side effect, with tenderness being the most common result.

Approximately 34% of people had systemic side effects after the first dose of the AstraZeneca vaccine, with headache and fatigue being the main symptom, followed by chills and chills.

Similar to Pfizer, allergic reactions are rare after receiving the AstraZeneca vaccine. Less than two percent of people report skin burns and less than one percent of people report rashes and red welts on their faces and lips.

Bogoch said that while side effects are common and can be expected, most people do not experience them.

« Depending on the vaccine you are given and your age, there will be a 10% to 20% change in having some of these side effects. » he said. « Most people do not experience these side effects and while they still do occur the vast majority of them are mild and resolve on their own. »

For more severe reactions with either vaccine, Bogoch said they are far less common.

« Serious reactions are extremely rare, » he said. « We know that anaphylaxis events are extremely rare, but every vaccine administration center is prepared when they do. »

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