NIH to Study Allergic Reactions to mRNA Vaccines

April 14, 2021

The NIH is sponsoring a clinical trial focusing on the risk of allergic reactions to Moderna and Pfizer’s mRNA vaccines. The COVID-19 mRNA vaccines are the first mRNA vaccines to be authorized by the FDA. 
This clinical trial will “determine whether people who are highly allergic or have a mast cell disorder are at increased risk for an immediate, systemic allergic reaction to the Moderna or Pfizer-BioNTech COVID-19 vaccines.” A systemic allergic reaction is qualified as a vaccine reaction in one or more regions of the body outside of the injection site. A mast cell disorder occurs when mast cells (white blood cells) are overly active or behaving abnormally, causing allergic reactions. Investigators will also “examine the biological mechanism behind the reactions and whether a genetic pattern or other factors can predict who is at most risk.”

Investigators aim to enroll 3,400 adults, aged 18-69, across 35 allergy-research centers. Approximately 60% of participants will need to have a history of “severe allergic reactions or a diagnosis of a mast cell disorder.” Allergic reactions can be related to food, insect stings, or allergen immunotherapy that requires treatment with an epi-pen (epinephrine). Participants may also enroll if they have a history of immediate allergic reactions to a vaccine or one or more drugs. This study plans to enroll more women than men, as women account for the majority of severe allergic reactions to the COVID-19 vaccine. 
The clinical trial is currently enrolling participants.