Do marshmallows make your tongue swell? Gummy bears make you itchy? If you’ve answered yes and are allergic to gelatin, you will want to take some precautions when getting the flu shot. While the vaccine is recommended for those six months of age and older, a case report being presented at the American College of Allergy, Asthma and Immunology (ACAAI) Annual Scientific Meeting notes that individuals with a gelatin allergy can have a mild to severe reaction from the shot.

“Gelatin is used in the flu shot, as well as other vaccines, as a stabilizer,” said Stephanie Albin, MD, an allergist and ACAAI member. “Because it is found in the vaccine, those with a known allergy to gelatin can experience allergic reactions, such as hives, sneezing and difficulty breathing.”