Vaccines

A guide to vaccines & alpha-gal syndrome (AGS)

AGS & vaccines

Gelatin &
Vaccines

Graded dosing

More info

Publications

Alpha-gal syndrome and vaccines

Guidance for patients with AGS: should not receive vaccines with gelatin, if possible.
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Vaccines are also an important source of gelatin exposure, including Zostavax and MMR. Cases of reactions to these vaccines in patients with alpha-gal IgE have been reported. 

Commins SP. Diagnosis & management of alpha-gal syndrome: lessons from 2,500 patients. Expert Rev Clin Immunol. 2020;16(7):667-677.

Gelatin is present in some vaccines, including Zostavax and MMR. Cases of reactions to these vaccines in patients with IgE to α-Gal have been reported.

Platts-Mills TAE, Li RC, Keshavarz B, Smith AR, Wilson JM. Diagnosis and Management of Patients with the α-Gal Syndrome. J Allergy Clin Immunol Pract. 2020;8(1):15-23.e1.

Animal-derived products used in vaccine manufacture can include amino acids, glycerol, detergents, gelatin, enzymes and blood. Cow milk is a source of amino acids, and sugars such as galactose. Cow tallow derivatives used in vaccine manufacture include glycerol. Gelatin and some amino acids come from cow bones. Cow skeletal muscle is used to prepare broths used in certain complex media. Many difficult to grow microorganisms and the cells that are used to propagate viruses require the addition of serum from blood to the growth media.

Center for Biologics Evaluation, Research. Bovine Derived Materials Used in Vaccine Manufacturing Questions and Answers. U.S. Food and Drug Administration. Published August 2, 2022. Accessed March 8, 2025. https://www.fda.gov/vaccines-blood-biologics/bovine-derived-materials-used-vaccine-manufacturing-questions-and-answers

Some vaccines contain gelatin, and there are published reports of alpha-gal-related reactions to gelatin-containing vaccines.  

Experts recommend that people with AGS avoid vaccines that contain gelatin when possible. When a provider deems that the potential benefits of a gelatin-containing vaccine outweigh the potential risks,  precautions such as premedication, graded dosing, and medical supervision may be considered.

In addition to gelatin, vaccines may contain other mammal-derived excipients or residual traces of mammal-derived ingredients used in the manufacturing process. Other vaccines are made in mammalian cell lines. There is a lack of data on the risk of reactions associated with these vaccines.

Boostrix and Flucelvax are two vaccines that do not contain gelatin but may be best avoided by patients with AGS when alternatives are available, per one expert (personal communication).

It’s important to understand that sometimes the benefit of a vaccine outweighs the risk of a reaction, for example, a rabies vaccine in the event of a bite from a potentially rabid animal.  

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Gelatin in vaccines

Based upon agreement between skin and ex vivo testing, MMR and/or varicella vaccines appear to have been the cause of our alpha-gal allergic patient’s vaccine-associated anaphylaxis. We have previously demonstrated that MMR and zoster vaccine can bind and deplete sIgE to alpha-gal. We now show that MMRV and varicella vaccine also demonstrate binding and depletion of alpha-gal sIgE.

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Both this alpha-gal allergic child and our previous alpha-gal allergic adult who reacted to alpha-gal/gelatin-containing vaccines had low serum concentrations of gelatin sIgE.

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Notably, alpha-gal allergic patients have been reported to react to gelatin even with negative gelatin sIgE.

Stone CA Jr, Commins SP, Choudhary S, et al. Anaphylaxis after vaccination in a pediatric patient: further implicating alpha-gal allergy. J Allergy Clin Immunol Pract. 2019;7(1):322-324.e2.

Warning and disclaimer

  • This information is incomplete.
  • Some vaccines that do not contain gelatin may contain other sources of alpha-gal, including mammal-derived excipients and residues from the manufacturing process. Moreover, some may be made in mammalian cell lines. 
  • You must confirm this information. We have done our best to provide accurate information, but we are not medical professionals and cannot guarantee its accuracy. It is the provider’s responsibility to confirm the content of vaccines and determine their safety for individual patients. 
  • This information does NOT constitute a recommendation or medical advice.

If you are a patient, please seek the advice of a physician about vaccine decisions.

 

 

Vaccine type Contain gelatin Do NOT contain gelatin (may contain other mammal-derived excipients or residues or be made in mammalian cell lines)
Flu (for 2024) Flumist
Quantity per dose: 2 mg		 *Flulaval quadrivalent
*Fluzone quad and high-dose
*Flublok quad
*Fluad
*Afluria
MMR

• MMR II (measles, mumps, rubella)
Quantity per dose: 14.5 mg
MMR-II

• ProQuad (measles, mumps, rubella, varicella)
Quantity per dose: 11 mg

 *Priorix
Varicella zoster Zostavax (not currently available in the U.S.) *Shingrix
Varicella zoster Varivax
Quantity per dose: 8.9-12.5 mg		 ?
Typhoid Vivotif (oral Typhoid)
Quantity per dose: Gelatin capsule		 Typhim Vi
Rabies Rabavert
Quantity per dose: ≤ 12 mg		 Imovax
Yellow fever YF-Vax
Quantity per dose: not specified		 Stamaril
Covid *Moderna
*Pfizer
Tetanus/TDaP *Adacel
RSV Arexvy
Abrysvo
Meningitis Menveo
Trumenba

 

* At least one expert reports anecdotally that overall, the majority of their patients who have received this product thus far have reported that they tolerated it (personal communication).

Sources:

Graded dosing

Summary Statement 9: In a patient with a history and skin test results consistent with an IgE-mediated reaction to a vaccine who requires additional doses of the suspect vaccine or other vaccines with common ingredients, consideration can be given to administering the vaccine in graded doses under observation. (C)

If vaccine or vaccine component skin test results are positive, the vaccine might still be administered, if necessary, in graded doses (Table V). If the full vaccine dose is normally a volume of 0.5 mL, the patient is first given 0.05 mL of a 1:10 dilution and then given full-strength vaccine (at 15-minute intervals) at doses of 0.05, 0.1, 0.15, and finally 0.2 mL, for a cumulative dose of 0.5 mL.

This procedure in a patient who is presumed to be allergic to the vaccine being administered needs to be performed under direct medical supervision, with emergency medications and equipment immediately available to promptly treat an anaphylactic reaction should it occur. Such challenges can be performed in an office or hospital setting with or without an intravenous line in place, depending on the severity of the original reaction to the vaccine and the patient’s medical condition.

Kelso JM, Greenhawt MJ, Li JT, et al. Adverse reactions to vaccines practice parameter 2012 update. J Allergy Clin Immunol. 2012;130(1):25-43.

See the below vaccine parameter update for more information:

More information

From Johns Hopkins Institute for Vaccine Safety:

 

 

From VeganMed:

  • Is the COVID-19 Vaccine Vegan?*
    * Note that this article does not reflect that we confirmed, via the Swedish Medical Association, that the Pfizer Covid vaccine has no detectable casein in the final product. 

 

 

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