Food Allergy Resources

How Food Ingredients in Vaccines Impact Food-Allergic Children

February 2009

Do immunizations contain food allergens?

A review of vaccine safety for food allergic children

Vaccines have immeasurably improved health care and have eased the effects of disease. They not only contain the virus or bacterial components necessary to activate the immune system against the disease, but they contain various preservatives, adjuvants, stabilizers and other residual material.

Of these latter items, the food related ingredients of lactose, gelatin, egg protein, and yeast protein may be available in sufficient quantities to cause reactions in susceptible persons. Happily, these events are rare.

Vaccine reactions

The Vaccine Adverse Reporting System (VAERS) is a national passive event reporting system, that anyone can report any type of perceived reaction to any vaccination. Of data compiled between 1991 and 2001, there were 128,717 adverse event reports from an estimated 1.9 billion vaccinations, of which only 14.2% resulted in serious consequences. Of these serious consequences, death could be roughly correlated as less than 2%. Shortcomings of the VAERS include under reporting, incomplete or inaccurate reporting, biased reporting, and lack of proof of actual causes of the adverse events. Still it is an important resource to monitor unusual or new adverse effects.

Milk allergy: lactose in vaccines

Lactose is currently listed in the inactive ingredients in only one vaccine in common use in the United States – Menomune®, a vaccine for meningococcal disease.  It contains 2.5 to 5.0 mg of lactose per 0.5ml dose. Fortunately, Menactra® is another, preferred vaccine for immunization against the same disease and does not contain lactose. While Infanrix® and Pediarix® list bovine casein and bovine casein plus lactalbumin respectively in the culture components, this does not seem to be a problem in milk-allergic children and should not be a reason to avoid vaccination with these products.

Pork allergy: gelatin in vaccines

Gelatin that is in vaccines is a stabilizer and in the United States is present in a highly hydrolyzed (broken down) state, therefore less likely to cause reactions. The gelatin, uniformly, is of porcine (pork) origin. The American Academy of Pediatrics (AAP) has stated that the incidence of anaphylaxis to gelatin is 1 case per 2 million doses. They further recommend that children with either a history of food allergy to gelatin or a history of immediate-type hypersensitivity reactions to gelatin-containing vaccines receive immunologic testing prior to getting any further gelatin-containing vaccines.

Egg allergy: egg protein in vaccines

Egg allergies occur in approximately 0.5% of the population, mostly children. Residual egg proteins may be available in yellow fever and influenza vaccines in amounts of 0.02 to 1.0 micrograms per dose. This may be sufficient to cause reactions in some individuals.  Manufacturers are not required to report how much egg protein is in each vaccine and quantities may vary with each batch and year of the vaccine.

Since children with egg allergies often have other diseases, such as asthma, they may be at high risk of severe influenza infections.  An allergist, after testing, may recommend a strict protocol whereby the influenza vaccine is given in divided doses with careful monitoring. Alternatively, the allergist may recommend the use of prophylactic medications, such as Tamiflu® (oseltamivir), Relenza® (zanamivir), or Symmetrel® (amantadine).

There has been one recent report in the International Archives of Allergy and Immunology in which a patient is described as having an anaphylactic reaction to an influenza vaccine. Based on clinical symptoms, skin testing, Immunocap® testing, and immunoblot evaluation, the authors felt that patient was allergic to the infectious agent in the influenza vaccine as well as gelatin and ovalbumin contained in the vaccine.

The amount of egg proteins found in measles and mumps vaccines is not sufficient to produce an immediate-type of hypersensitivity reaction and children with severe egg allergies can receive these vaccines safely.

Yeast ingredients in hepatitis B vaccine

Reactions to the residual yeast components in vaccines are rare, with yeast-specific IgE not being detected in patients with immediate-type hypersensitivity reactions after hepatitis B vaccine. The AAP, therefore, states that the risk of anaphylaxis after receipt of hepatitis B vaccine as a result of allergy to baker's yeast is theoretical.

Consult your allergist

Please note that evaluation by an allergist is critical when a suspected hypersensitivity reaction to a vaccine has occurred. Likewise, since each child with food allergies has conditions unique to his/her case, an allergist should be consulted for any questions regarding the safety of vaccinations in that child, rather than foregoing vaccinations completely.


References:

1. Coop, C., Balanon, S., White, K., Whisman, B., & Rathkopf, M. (2008) Anaphylaxis from the Influenza Virus Vaccine. Int Arch Allergy Immunol. 146, 85-88.
2. Offit, P., & Jew, R. (2003). Addressing Parent's Concerns: Do Vaccines Contain Harmful Preservatives, Adjuvants, Additives, or Residuals?, Pediatrics. 112, 1394-1397.
3. Song, B., & Katial, R. (2004). Update on Side Effects from Common Vaccines. Curr Allergy and Asthma Rep. 4, 447-453
4. Zeiger, R. (2002). Current Issues with Influenza Vaccination in Egg Allergy. J Allergy Clin Immunol. 110, 834-40.

Resources:

Centers for Disease Control and Prevention. (2009). Advisory Commitee on Immunization Practices (ACIP). Retrived from the World Wide Web, www.cdc.gov

American Academy of Pediatrics. (2009). Immunizations/Vaccines. Retrieved from the World Wide Web, http://www.aap.org

Department of Health and Human Services. (2008). Vaccine Adverse Event Reporting System. Retrieved form the World Wide Web, http://www.vaers.hhs.gov


Approved by KFA's Medical Advisory Team January 2009. Updated February 2010.