New NIH study to gauge risk of allergic reactions to Pfizer, Moderna vaccines

New NIH study to gauge risk of allergic reactions to Pfizer, Moderna vaccines
© Greg Nash

The National Institutes of Health (NIH) announced Wednesday that it's launching a study to gauge the risk of allergic reactions to the Pfizer-BioNTech and Moderna vaccines among certain individuals.

The research seeks to determine whether people who are highly allergic or have mast cell disorders — an illness when a white blood cell is abnormal and overly reactive — are more likely to have a systemic allergic reaction to either vaccine.

Data from the study, which is sponsored and funded by the National Institute of Allergy and Infectious Diseases (NIAID), is expected to be released in late summer.


The NIAID plans to recruit 3,400 adults under the age of 70 for the study, with about 60 percent of participants having a history of severe allergic reactions or a diagnosis of a mast cell disorder.

If any participants experience an allergic reaction, researchers will provide immediate medical care and then examine if those reactions are more common among people who are highly allergic or with mast cell disorders than those without an allergy history.

The study’s participants will randomly be chosen to get the Pfizer vaccine, the Moderna vaccine, a placebo followed by the Pfizer vaccine or a placebo followed by the Moderna vaccine.

NIAID Director Anthony FauciAnthony FauciAstraZeneca CEO: 'Not clear yet' if boosters are needed St. Louis official says he was targeted with racist slurs over mask promotion McConnell: 'It never occurred to me' convincing Americans to get vaccinated would be difficult MORE said in a release that Americans “understandably have been concerned” about reports of allergic reactions after taking the COVID-19 vaccine.

"The information gathered during this trial will help doctors advise people who are highly allergic or have a mast cell disorder about the risks and benefits of receiving these two vaccines,” Fauci said in a statement. “However, for most people, the benefits of COVID-19 vaccination far outweigh the risks.”

The Food and Drug Administration approved both of the vaccines in December, before authorizing emergency use of the Johnson & Johnson vaccine this year.

The Centers for Disease Control and Prevention estimated in January that 11.1 cases of allergic reaction occurred per 1 million doses of the Pfizer vaccine.

Most of the allergic reactions to COVID-19 vaccines in the U.S. have involved individuals with a history of allergies, with several reporting they had previously experienced a life-threatening allergic reaction.