Gelatin is contained in some vaccines to protect vaccine viruses from adverse conditions such as freeze-drying or heat (see table below). Gelatin is a protein formed by boiling skin or connective tissue. Gelatin is used to stabilize vaccines so that they remain effective after manufacture. All gelatin contained in vaccines is porcine in origin.
Gelatin content of vaccines licensed in the United States, 2016
Measles, mumps, rubella (MMR II®)
Quantity per dose: 14.5 mg
Measles, mumps, rubella, varicella (ProQuad®)
Quantity per dose: 11 mg
Quantity per dose: < 12 mg
Shingles (zoster) (Zostavax®)
Quantity per dose: 15.58 mg
Typhoid oral (Vivotif®)
Quantity per dose: Gelatin capsule
Quantity per dose: 12.5 mg
In 1993, Kelso and co-workers reported the case of a 17-year-old girl in California who developed a severe allergic reaction (hives, low blood pressure, runny nose and lightheadedness) within five minutes of receiving an MMR (measles, mumps and rubella) vaccine. Her symptoms resolved after treatment with epinephrine. When later describing the event, the girl stated that it was “kind of like what happens when I eat Jell-O®.” Subsequent testing found that the only component of the vaccine to which this girl was allergic was gelatin.
Studies in Japan confirmed the findings of Kelso and colleagues that severe allergic reactions to MMR vaccine were associated with the presence of antibodies in the blood directed against gelatin. Although the incidence of anaphylaxis to gelatin is extremely low (about 1 case per 2 million doses), gelatin is the most common identifiable cause of severe allergic reactions to vaccines.
Some people with severe allergic reactions to gelatin have a history of allergies to foods that contain gelatin. This is explained, in part, by similarities between the bovine gelatin contained in many foods and the porcine gelatin contained in vaccines. Therefore, it would be good to know about possible allergies to gelatin before getting a vaccine that contains gelatin. People with severe allergies to gelatin should avoid gelatin-containing vaccines.
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Sakaguchi M, Nakayama T, Fujita H, et al. Minimum estimated incidence in Japan of anaphylaxis to live virus vaccines including gelatin. Vaccine. 2001;19:431-436.
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