COVID-19 Shot Safe for Most PEG Allergy; Latinos See Asthma Flares

in Food Allergy, Food Allergy News
Published: November 8, 2021

PEG Allergy? You Likely Can Get the Vaccine

People with a polyethylene glycol (PEG) allergy appear to be able to receive any of the three COVID-19 vaccines available in the U.S. with little risk of an allergic reaction, new research suggests. 

When the COVID-19 mRNA vaccines made by Pfizer-BioNTech and Moderna were rolled out in late 2020, there was intense speculation that reports of rare anaphylaxis might be due to an allergy to PEG. It is an ingredient in the mRNA vaccines. 

Researchers from the Mayo Clinic decided to investigate. They scoured their health records and identified 100 patients who had a PEG allergy noted in their medical records. Nonetheless, all received two doses of the Pfizer or Moderna mRNA vaccine, or one dose of the J&J vaccine, without any symptoms of an allergic reaction. 

Dr. Mitchell Pitlick

The study found that a majority of these patients likely didn’t have a “true allergy” to PEG which, though rare, can be severe. The patients largely reported gastrointestinal symptoms to PEG, which can be an expected side effect, without other allergy symptoms. 

“What this study is suggesting is that people who have an allergy label to PEG might be able to tolerate these vaccines just fine, without significant risk of allergic reaction,” says lead study author Dr. Mitchell Pitlick, an allergy fellow at the Mayo Clinic in Rochester, Minnesota. The study was presented at the 2021 American College of Allergy, Asthma and Immunology (ACAAI) annual conference in New Orleans. 

Anaphylaxis after a COVID-19 mRNA vaccine is extremely rare, occurring in 7.9 people per 1 million COVID-19 shots, according to a recent analysis. Because the mRNA vaccines contain only a short list of ingredients – and no food or animal products, preservatives, drugs or latex – the reasons for the rare severe allergic reactions have remained unclear. 

Some thought the reactions could be caused by PEG, an oily sphere that protects the mRNA during injection. PEG can be found in numerous consumer products, including laxatives, shampoos and toothpaste. 

Is It a True PEG Allergy?

In the Mayo study, about 64 patients received the Pfizer-BioNTech vaccine, 33 got Moderna and three had Johnson & Johnson. The patients were mostly women with an average age of 69.

About 84 percent reported a previous reaction to PEG either in an over-the-counter laxative or an oral prep used to empty the bowels before a colonoscopy. Smaller numbers reported reacting to an injected medication, eye drops or topical cream containing PEG. 

About 38 percent had experienced “gastrointestinal intolerance” with PEG, such as diarrhea, nausea or vomiting. Pitlick notes that these can either be normal effects of laxatives, or common side effects, especially when drinking a large volume of colonoscopy prep solution.

“Those symptoms are nothing that would be suggestive of an allergy in the absence of other allergic symptoms,” he says. 

About 29 percent reported a rash, hives or itching, and some others had symptoms unrelated to allergy. Five percent were reported as having anaphylaxis. However, Pitlick notes that a missing piece is how long after exposure to PEG the symptoms occurred. Allergic reactions tend to happen within an hour. 

The findings suggest that many people who think they have a PEG allergy may not be truly allergic, and that PEG is unlikely to be the cause of most of the rare anaphylactic reactions reported to the vaccines.  

Concerns about PEG prompted the CDC to warn people allergic to PEG not to get an mRNA vaccine, while those allergic to polysorbate, an ingredient in the J&J shot, were told not to get that vaccine. 

Pitlick says anyone who is worried they may have a PEG allergy should talk to their doctor about it. He adds that physicians shouldn’t automatically tell those patients not to be vaccinated.

“PEG has not been proven to be a culprit allergen in these vaccines,” he says. “And the overall risk of reaction to these vaccines is still extremely low.” 

Asthma Flares Worse for Latinos with COVID-19 

COVID-19 hit minority communities particularly hard. New research finds that applies to asthma exacerbations as well. 

Latinos with asthma were more likely than either whites or Blacks to suffer an asthma exacerbation after becoming infected with COVID-19, according to a study by researchers at Rush University Medical Center in Chicago. 

Their asthma exacerbations also lasted longer – an average of 3.2 weeks for Latinos, compared to 1.4 weeks for Blacks and 1.5 weeks for whites. 

The study, also presented at the ACAAI meeting, included 174 adults with asthma who were seen in a Rush University emergency department, a physician’s office or a telehealth visit between February and April 2020. 

Despite having uncontrolled asthma symptoms that lingered for longer, Latinos did not have any more doctors’ visits than whites or Blacks. “It’s a reminder for providers treating Latino patients with asthma who may have been exposed to COVID to be proactive in seeing them for follow-up visits and aggressively considering if they are candidates for step-up therapy for their asthma,” says lead study author Dr. Katharine Foster. 

COVID-19, like other viruses that affect the upper respiratory tract, can lead asthma symptoms to flare. However, studies have not consistently shown how often COVID-19 leads to asthma exacerbation. Foster, an internal medicine resident at Rush, says estimates of the risk range from 20 percent to as high as 75 percent. Rhinoviruses, which cause the common cold, bring a 40 to 50 percent chance of an asthma exacerbation. 

Before COVID, Most Had Mild Asthma

Researchers don’t know whether the Latino patients had worse asthma than the other groups at the time they contracted the virus. However, Foster says none were experiencing an exacerbation when they got sick. Most had mild intermittent or mild persistent asthma; only eight had severe persistent asthma. 

All but one person has since recovered from the asthma exacerbation. “Only one patient with severe, persistent asthma never got back to baseline. Four months out, they were still feeling they could not catch their breath and were still needing albuterol [the rescue inhaler] all the time,” Foster says. “It was something they had not experienced before COVID.”  

She urged anyone with asthma to get vaccinated. “It does so much for protecting you, your family members and anyone you interact with,” she says. “It’s always important to consider how to protect yourself from an asthma exacerbation.”  

Related Reading:
COVID-19 Vaccines: How to Tell an Allergic Reaction from a Side Effect
FAQ on: Allergy Concerns and the mRNA COVID-19 Vaccine