If putting marshmallows in your hot chocolate or eating gummy bears makes your tongue swell or causes itchiness, experts say you may want to be cautious about getting a flu shot this winter, as certain vaccines contain gelatin.

As flu vaccine coverage is on the rise in the US, experts from the American College of Allergy, Asthma and Immunology (ACAAI) warn that individuals who are allergic to gelatin could have a mild to severe reaction to the flu vaccine.

According to the Centers for Disease Control and Prevention (CDC), everyone who is 6 months or older should get a flu vaccination this season.

The vaccine can be administered as either a shot or as a nasal spray, but both forms can contain gelatin, as Dr. Stephanie Albin, an allergist and ACAAI member, says:

Gelatin is used in the flu shot, as well as other vaccines, as a stabilizer. 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.”

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Does eating these make your tongue swell? You may want to take caution when considering a flu shot.

Gelatin is also found in various food and pharmaceuticals, and it can contain cow, pig or fish proteins.

Dr. Albin notes that reactions to gelatin can cause a variety of symptoms, including hives, swelling, itchiness, shortness of breath and anaphylaxis, which is life-threatening.

“Because of this,” she says, “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.”

The ACAAI has said although there is a misconception that individuals with egg allergies should not receive a flu vaccination, the organization recently published findings that those with severe egg allergies can actually get a flu vaccine without any special precautions.

Dr. Richard Weber, president of ACAAI, says that allergies to gelatin are not very common, and he notes that food intolerances can mistakenly be perceived as allergies. He says:

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 who are at an increased risk for severe side effects associated with the flu.”

Recently, there have been studies suggesting other benefits of the flu vaccine, such as lower heart attack risks, and Medical News Today recently reported that pregnant women can safely take the H1N1 flu vaccine.