The form of PEG matters: PEG conjugated with lipids and not PEG alone
could be the specific form involved in allergic reactions to COVID-19
vaccines
Abstract
Initial guidelines advised that sensitization to PEG should be taken
into consideration in suspected subjects before a recommendation on the
administration of vaccines for COVID-19 containing PEG or its
cross-reactive analogues. 3 However, PEG shows an
important variability in terms of molecular weights and conjugation
forms. In that sense, although it is known that PEG-2000 (MW: 2000g/mol)
conjugated with lipids is the form contained in the vaccines for
COVID-19, there has been great variability in the PEG molecules used in
allergy tests to evaluate sensitization of suspected subjects in the
context of the current COVID-19 vaccination campaigns.
4 In this context, recent findings have shed light on
the specific form of PEG that could be responsible of the
hypersensitivity reactions to the mRNA vaccines for COVID-19.