On the CDC’s webpage for “Who Should NOT Get Vaccinated with these Vaccines?”, there is a recommendation under many of the vaccines against those with a previously recognized severe allergic reactions to any of the vaccine components receiving that vaccination [1].  This seems intuitive, however it presents an interesting challenge for patients that require a specific vaccination, but have a history of allergic reaction to one of its nonmicrobial components (including components of culture media, adjuvants, preservatives, stabilizers, antimicrobial agents, and additives) [2].   Common examples of these potential allergens include: egg, gelatin, and cow’s milk.  An in depth listing of possible allergens from common vaccines is available at the Institute for Vaccine Safety (at John Hopkins School for Public Health) at the following link [3]: http://www.vaccinesafety.edu/components-Allergens.htm

So how can patients with known or suspected severe allergies to vaccine components be vaccinated?

Firstly, it is important to recognize these components are not necessarily included at high enough levels to be clinically significant (ie. trigger an allergic reaction) [2,4].  This issue has proven somewhat controversial and complex, with disagreement in scholarly literature about if specific ingredients are present in high enough quantities to require special treatment when given to those with a history of severe allergic reactions [2].  For an interesting example, see the discussion on MMR vaccines and egg allergies in the referenced study (below) by Franceschini et al. 2015 [2].

When no alternative vaccine is available and the allergen is present at high enough quantity to be of concern, allergological studies can be used to access risk of allergic reactions upon vaccination.  The exact steps differ between different vaccines and allergens, however typically skin allergy testing (diluted or whole vaccine is inserted in skins though intraepidermal puncture, intradermal injection or epicutaneous patch) or serological tests for serum specific IgE (Immuno-CAP technique) are utilized [4].  If the patient exhibits negative test results, then the vaccine can be administered normally, with an added observation period of approximately 1 hour in the hospital or doctor's offfice to ensure no adverse events occur.  If the test(s) are positive, in some cases, vaccines can still be administered incrementally in a controlled, hospital environment [2,4].  A more detailed description about this procedures for specific vaccine components can be found as Table 2 within the review by Franceschini et al. (2015) at the following link [2] : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4384976/table/Tab2/

Look forward to hearing your thoughts on this!

References

1.  CDC. Who Should NOT Get Vaccinated with these Vaccines? (Last updated: July 20, 2016.) Retrieved from: http://www.cdc.gov/vaccines/vpd-vac/should-not-vacc.htm

2.  Franceschini, F., Bottau, P., Caimmi, S., Crisafulli, G., Lucia, L., Peroni, D., . . . Caffarelli, C. (2015). Vaccination in children with allergy to non active vaccine components. Clinical and Translational Medicine, 4(1), 1-8. 

3.  Institute for Vaccine Safety, John Hopkins School of Public Health.  Allergens. (Last Updated: September 22, 2016). Retrieved from: http://www.vaccinesafety.edu/components-Allergens.htm

4.  Echeverría-Zudaire, L. A., Ortigosa-del Castillo, L., Alonso-Lebrero, E., Álvarez-García, F. J., Cortés-Álvarez, N., García-Sánchez, N., & Martorell-Aragonés, A. (2015). Consensus document on the approach to children with allergic reactions after vaccination or allergy to vaccine components. Allergologia Et Immunopathologia, 43(3), 304.