Individuals with a gelatin allergy can have a mild to severe reaction from the flu vaccine, according to research presented at the American College of Allergy, Asthma and Immunology (ACAAI) Annual Scientific Meeting.

Still, avoiding the shot altogether is not necessarily the best approach. Clinicians recommend patients undergo testing before passing on the influenza vaccine.

“Gelatin allergy is very rare. Many food intolerances can be mistaken as allergies,” said allergist Richard Weber, MD, ACAAI president. “Those who believe they might have an allergy should be tested and diagnosed by an allergist before taking extreme avoidance measures or skipping vaccinations. The flu shot is an important vaccine and can even be life-saving for individuals that are at an increased risk for severe side effects associated with the flu.”

“Gelatin reactions can cause hives, swelling, itchiness, shortness of breath, and a severe life-threatening reaction known as anaphylaxis,” said Stephanie Albin, MD, an allergist and ACAAI member, who explained gelatin is used in vaccines as a stabilizer. “Because of this, precautions should be taken, such as having a board-certified allergist administer the vaccine in a person with known gelatin allergy in case a reaction occurs.”