The University of South Florida is participating in a national study to examine whether people with a history of allergies are more at risk for severe reactions to the Moderna and Pfizer-BioNTech coronavirus vaccines.
The study is sponsored by the National Institute of Allergy and Infectious Diseases, which is part of the National Institutes of Health. In addition to USF, researchers will draw information from 28 other sites around the country.
While the number of severe reactions to the vaccines was low during initial observations, the rate was significant. It was 10 times that of most other vaccines for the Pfizer drug and 2.5 times higher for the Moderna vaccine, said Dr. Thomas Casale, principal investigator at USF and chief medical advisor of Food Allergy Research and Education.
Scientists noticed those who had a mast cell disorder or history of severe allergies — whether to food, venom or medications — tended to be more likely to have severe reactions. But the vaccine itself contains none of those components, Casale said.
Some have speculated that the problem is with the compounds added to the vaccine to improve its solubility, keep it sterile and stabilized and stimulate an immune response. But those same compounds are used in other vaccines and medications, Casale said. The specific molecular weight, he said, could impact it.
“They haven’t been proven to be the culprits yet,” he said. “Hopefully this study will help find whatever it might be.”
The study will attempt to enroll 3,400 participants between the ages of 18 and 69 across all the sites. About two-thirds of the participants will have severe allergies and the others will have no history of allergies.
All participants eventually will receive a vaccine, but at the beginning of the study, each will receive a Moderna, Pfizer or placebo vaccine. All participants will be monitored for 90 minutes. Those who experience allergic reactions will be treated, and later studied through blood work and genetic testing.
“There’s still unfortunately a number of people that have vaccine hesitancy,” Casale said. “I think that some of it could be because of these histories of allergic reactions, certainly not all of it. But at least in those people that are hesitant to get the vaccine because they have a history of severe allergies, this will be a way for them to help scientists understand those particular allergic reactions and be able to get the vaccines in a safe environment where physicians will be able to treat them if they did have an acute allergic reaction.”
For most people, the benefit of getting a coronavirus vaccine still “far outweighs the risk,” said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and chief medical advisor to the president. The study, he said in a news release, will help doctors better advise their higher-risk patients.
Casale said he’s heard of misinformation circulating about the vaccine. Some of his patients thought they couldn’t take some because of their allergies, when the vaccines themselves contain none of the things they’re allergic to.
“It’s very important to do these types of studies not only to assure the public about what might be causing these types of reactions, but also enable them to get it in a safe environment,” Casale said.
For more information about the study, click here.