Togias said researchers at the NIAID, an agency within the National Institutes of Health, became interested in the rare phenomenon after reports that a few people had reactions to Pfizer s vaccine that qualified as anaphylaxis, a severe and potentially life-threatening allergic reaction. Just last week, a clinician in Alaska suffered anaphylactic symptoms about 10 minutes after being given Pfizer s vaccine, becoming the third health-care worker in the state to suffer an adverse reaction to the new drug. We are a little bit concerned that people who have had a lot of allergies who have had reactions like this to all kinds of things, not just vaccines, may be afraid to get vaccinated now, Togias told CNBC. We just don t want that to happen. We want to find a way for them to get vaccinated, he added.