PEG, penicillin and proceeding with mRNA vaccine
Question:
8/17/2021
Initially when COVID-19 vaccines arrived, PEG and polysorbate were named as reasons for allergic reactions. Later we read PEG could be in different products including parenteral antibiotics such as penicillin. Now those references are difficult to find. Is penicillin IM or IV a product that could produce reactions due to PEG content? How do you proceed after a history of pcn anaphylaxis after parenteral administration on somebody interested in being vaccinated for COVID-19?
Answer:
The cause of these vaccine anaphylaxis cases is unclear, but polyethylene glycol (PEG) is a candidate allergen in mRNA vaccines, though to my knowledge, that this has not been confirmed. Most immediate onset mRNA vaccine reactions may not be mechanistically caused by Ig-E-mediated hypersensitivity. Complement-activation–related pseudo-allergy (CARPA) has also been proposed as a potential etiology. In studies addressing immediate reactions to mRNA vaccine (1,2), the majority of patients that experienced immediate reaction went on to tolerate the 2nd dose without recurrence of immediate reaction. Anecdotally, in our clinic, after testing negative for PEG and tolerating an oral challenge, patients went on to receive their 2nd dose without reaction.
Polyethylene Glycol is commonly used as carrier molecules in liquid or solid type medications. It is used to conjugate with medications to improve their efficiency, their effectiveness and ability to generate an immune response. PEG is found in many skin care products, cosmetics, food products and oral products such as cough syrups and laxatives. PEG is the active ingredient in bowel preps and in the past 15 years, there have been 55 reported cases of anaphylaxis associated with oral ingestion of PEG containing bowel preps.
I searched several sites and could not find a reference to Penicillin containing PEG. Based on CDC guideline, penicillin allergy (even anaphylaxis) is not a contraindication to receiving the mRNA Sars-Co-V-2 vaccine, though should be advised to be observed 30 minutes after the COVID-19 vaccine.
1) Krantz MS, Kwah JH, Stone CA Jr, Phillips EJ, Ortega G, Banerji A, Blumenthal KG. Safety Evaluation of the Second Dose of Messenger RNA COVID-19 Vaccines in Patients With Immediate Reactions to the First Dose. JAMA Intern Med. 2021 Jul 26:e213779. doi: 10.1001/jamainternmed.2021.3779. Epub ahead of print. PMID: 34309623; PMCID: PMC8314170.
2) Banerji A, Wickner PG, Saff R, et al. mRNA Vaccines to Prevent COVID-19 Disease and Reported Allergic Reactions: Current Evidence and Suggested Approach. J Allergy Clin Immunol Pract. 2021;9(4):1423-1437. doi:10.1016/j.jaip.2020.12.047
I hope you find this helpful.
Respectfully submitted,
Jeffrey G Demain, MD, FAAAAI