When reports of serious allergic reactions among recipients of Covid-19 vaccines began to surface, Angelina Giunta was concerned.
Even though Giunta, 61, from Brooklyn, New York, was desperate to get the vaccine after a year in quarantine, she had two serious allergic reactions to medications during cancer treatment in 2017.
“I want to get the vaccine because I want to move on with my life,” said Giunta. “But I was extremely concerned.”
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Two ingredients in the Covid-19 vaccines, polyethylene glycol and polysorbate 80, have been suggested as possible culprits in the anaphylactic reactions related to the Covid-19 vaccines. (Anaphylaxis is a serious, life-threatening allergic reaction.) So far, however, the link has not been conclusively established.
Still, some allergy clinics in the United States have begun to point out that they are able to test patients for allergies to these ingredients.
But these tests, say many experts, can be a waste of time and resources – mainly because these allergies are incredibly rare.
Colleagues of mine who have been practicing allergies for 20 to 30 years can count on one hand the number of patients who have seen polyethylene glycol reactions.
“Colleagues of mine who have been practicing allergy for 20 to 30 years can count on one hand the number of patients who have seen reactions to polyethylene glycol,” said Dr. Paul Williams, an allergist at Northwest Asthma and Allergy Center in Seattle and a clinical professor of pediatrics at the University of Washington.
In fact, it is likely that the vast majority of Americans have already been exposed to polyethylene glycol or polysorbate 80.
Polyethylene glycol is a common active ingredient in over-the-counter laxatives. Pfizer-BioNTech and Moderna use it in their vaccines as a protective coating for messenger RNA, or mRNA, pieces of genetic code used to teach cells to recognize and fight the virus that causes Covid-19.
And polysorbate 80 is ubiquitous in the typical American diet, found in chewing gum, ice cream, puddings and other foods. It is used as an emulsifier to make products more creamy. It is also an ingredient in the Johnson & Johnson Covid-19 vaccine identified as a potential allergen – although no allergic reactions have been reported in Johnson & Johnson vaccine containers to date.
“There is nothing special about these vaccines in terms of allergic disease or anaphylaxis,” said Dr. Mitchell Grayson, president of Asthma and Allergy Foundation of the Medical Scientific Council of America. “Why aren’t we seeing more people with allergies to polyethylene glycol or polysorbate in general?”
Serious allergic reactions to the Covid-19 vaccine occurred at a rate of “2 to 5 people per million vaccinated in the United States,” the Center for Disease Control and Prevention said in a statement to NBC News. “Fortunately, vaccination providers have medications available to effectively and immediately treat patients who experience anaphylaxis after vaccination.”
In addition, screening and monitoring for such reactions has been considered in the Covid-19 vaccination protocol: this is why vaccine recipients are asked in advance whether they have ever had a severe allergic reaction to a vaccine and why they should wait 15 30 minutes after receiving the vaccine, so that, if a reaction occurs, the available medical staff can respond.
Grayson said the biggest problem with Covid-19 vaccines is not allergies, it is hesitation. Nearly a third of people who participated in a recent Kaiser Family Foundation survey said they prefer to wait and see what happens to other people who get the vaccine before rolling up their sleeves.
“My fear is that all of this is just helping to fuel this,” said Grayson, referring to the Covid-19 vaccine allergy test.
Who, if any, needs a test?
Charleston Allergy and Asthma, South Carolina, is a clinic that offers tests for polyethylene glycol and polysorbate 80. The tests are done by scratching a small amount of the substance in question on a person’s skin and watching for a reaction, such as redness or itching.
“We don’t know exactly at this moment what [vaccine] the components cause reactions in all of these different individuals, “said Dr. Meredith Moore, a clinic doctor.” But polyethylene glycol and polysorbate are the most likely culprits when you look at the ingredients in these two vaccines. “
None of the tests administered so far among Moore’s patients have been positive.
Moore said that most people with allergies do not have to worry about possible reactions to the Covid-19 vaccines.
In fact, for people who carry emergency adrenaline for peanuts, insects or other allergies, Moore advises against getting tested. She said allergy tests for polyethylene glycol or polysorbate 80 should be reserved for people with a history of allergic reactions with no known cause.
John Grabenstein, former executive director of medical affairs for vaccines at Merck and a former Department of Defense immunologist, said there was no evidence that the tests reduced the risk of any type of allergic reaction to the Covid-19 vaccine.
Since the ingredients have not been proven to be the cause of allergic reactions to the Covid-19 vaccine, having a negative allergy test to polyethylene glycol or polysorbate 80 does not necessarily mean that a person will be spared an allergic reaction to the vaccine. And a positive test should not prevent a person from receiving the Covid-19 vaccine, experts say.
“The vast majority of the public – even people with pollen allergies, people with penicillin and allergies to bee stings – don’t have to worry about vaccination,” said Grabenstein.
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Dr. Cascya Charlot, who offers the tests in her office at Brooklyn’s Allergy and Asthma Care, agrees.
“I am not advocating that everyone should have a skin test before receiving the vaccine, absolutely not,” said Charlot.
She sees the test as a way to dispel fears of allergic reactions to the Covid-19 vaccine.
“It is an incentive to public health, as far as we can see, to try to vaccinate people,” said Charlot. “We don’t want to worry about a possible reaction to the vaccine.”
None of the allergy tests Charlot did for polyethylene glycol or polysorbate 80 tested positive.
The harm in relying on these tests, Grayson said, would be to make someone “avoid a vaccine that they should otherwise be able to get”.
“Either you needlessly exclude people from a vaccine or you are allowing them to proceed with a vaccine, without knowing for sure whether they will have another anaphylactic reaction,” said Grayson.
The only positive effect appears to be peace of mind.
Giunta, one of Charlot’s patients, was negative and is looking forward to her Covid-19 vaccine.
“I want to move on with my life and travel, you know,” said Giunta, “doing the normal things I did before.”
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