Patients and procedures
Adult patients were included in this data analysis, if they met at least one of the following inclusion criteria: previous hypersensitivity reactions to vaccines or to medical products containing PEG or PS80, previous idiopathic anaphylaxis, and increased risk of developing anaphylaxis (e.g., because of mastocytosis). Patients were seen by an allergist and after taking a detailed medical history, the allergological workup was performed, including skin prick tests (SPT) and in selected cases also intradermal tests (IDT), as well as detection of total IgE and tryptase.
Since PEG and PS80 are suspected compounds to elicit hypersensitivity reactions, we included PEG2000, PEG6000 and PS80 in the test panel (SPT: 1%, 10%; IDT: 0.01%, 0.1%, dilution agent: sterile aqua). PEG and PS80 were purchased at Carl Roth (Karlsruhe, Germany). The powder of the substances was prepared by the local pharmacies for further testing. In some centers, Trometamol and 1,2-Distearoyl-sn-glycero-3-phosphocholine (DSCP) were applied for SPT at 1% and 10% (dilution agent: sterile aqua), these data will not be presented in this analysis. If available, the vaccines were tested undiluted in SPT and at 1% and 10% in IDT (dilution agent: sterile aqua). In individual cases, basophil activation tests (BAT) were performed with different compounds (i.e. PEG 2000, 1,2-Dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000 1,2-Dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000 1,2-Dimyristoyl-rac-glycero-3-methoxy-PEG 2000) in selected centers utilizing the Bühlmann Flow-CAST test (Bühlmann Laboratories AG; Basel, Switzerland) and the results were evaluated according to the company’s recommendations. Some centers followed internal protocols for the basophil activation tests, in which vaccine excipients were used at different concentrations for stimulation. The assessment of the clinical data for research proposes was approved by the ethics committee at the Charité (EA1/049/21) as the initiating center. All subjects gave written informed consent.