Gelatin is contained in some vaccines to protect vaccine viruses from adverse conditions such as freeze-drying or heat, particularly during transport and delivery (see table below). Gelatin is a protein formed by boiling skin or connective tissue. Gelatin contained in most vaccines is porcine in origin. An exception is one of the rabies vaccines, called Rabavert, which uses gelatin that is of bovine origin.

Gelatin content of vaccines licensed in the United States, 2019

Live, attenuated influenza (Flumist)

Quantity per dose: 2 mg

Measles, mumps, rubella (MMR II)

Quantity per dose: 14.5 mg

Measles, mumps, rubella, varicella (ProQuad)

Quantity per dose: 11 mg

Rabies (Rabavert)

Quantity per dose: ≤ 12 mg
Note: The gelatin product used in this vaccine is of bovine origin.

Typhoid oral (Vivotif)

Quantity per dose: Gelatin capsule

Varicella (Varivax)

Quantity per dose: 8.9-12.5 mg

Yellow fever (YF-Vax)

Quantity per dose: not specified

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.

References

Nakayama T, Aizawa C. Change in gelatin content of vaccines associated with reduction in reports of allergic reactions. J Allergy Clin Immunol. 2000;106:591-592.

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.

Sakaguchi M, Nakayama T, Inouye S. Food allergy to gelatin in children with systemic immediate-type reactions, including anaphylaxis, to vaccines. J Allergy Clin Immunol. 1996;98:1058-1061.

Sakaguchi M, Yamanaka T, Ikeda K, et al. IgE-mediated systemic reactions to gelatin included in the varicella vaccine. J Allergy Clin Immunol. 1997;99:263-264.

Sakaguchi M, Hori H, Ebihara T, et al. Reactivity of the immunoglobulin E in bovine gelatin-sensitive children to gelatins from other animals. Immunology. 1999;96:286-290.

Sakai Y, Yamoto R, Onuma M, et al. Non-antigenic and low allergic gelatin produced by specific digestion with enzyme-coupled matrix. Biol Pharm Bull. 1998;21:330-334.