Reply to “PEG skin testing for COVID-19 allergy”

To the Editor: We would like to thank Dr Bryan Stone for his correspondence1 to our manuscript “mRNA vaccines to prevent COVID-19 disease and reported allergic reactions: current evidence and suggested approach” in the Journal of Allergy and Clinical Immunology: In Practice 2 Current CDC guidance advises that any individual with an immediate or severe allergic reaction to the mRNA vaccine or any component of the vaccine (eg, polyethylene glycol [PEG] or polysorbate) should speak to an allergist before they receive the vaccine There are well-described cases of IgE-mediated allergy to PEG in the literature, and these cases have positive skin testing to PEG 3,4 PEG is also the only component of the currently available mRNA COVID-19 vaccines with a known nonirritating skin testing concentration reported in the literature 3 We do not have data on nonirritating skin testing concentrations for the mRNA vaccines themselves Given that there are no FDA-approved mRNA COVID-19 vaccines without PEG, consideration of skin testing with shared decision making offers a viable approach for individuals either with a clinical history suggestive of an IgE-mediated allergy to PEG or a potential anaphylactic reaction to the first dose of the mRNA COVID-19 vaccines (because PEG is the only available testable component)