Hypersensitivity Reactions to Anti-Sars-cov-2 Vaccines: Basophil Reactivity to Excipients.

Basophil activation test (BAT) can tackle multiple mechanisms underlying acute and delayed hypersen-sitivity to drugs and vaccines and might complement conventional allergy diagnostics but its role in anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine-related hypersensitivity is ill-defined. Therefore, 89 patients with possible hypersensitivity (56 % with delayed mucocutaneous manifestations) to anti-SARS-CoV-2 vaccines were tested with BAT for Macrogol 3350, DMG-PEG 2000, PEG 20000, polysorbate-80 and trometamol and compared to 156 subjects undergoing pre-vaccine BAT. A positive BAT was associated with delayed reaction onset (p = 0.010) and resolution (p = 0.011). BAT was more frequently positive to DMG-PEG 2000 than to other excipients in both groups (p < 0.001). DMG-PEG 2000 reactivity was less frequent in vaccine-naive (6 %) than vaccinated subjects (35 %, p < 0.001) and associated with mRNA-1273 vaccination. DMG-PEG 2000 BAT might therefore have a diagnostic role in subjects with delayed hypersensitivity reactions. Natural immunity might be a key player in basophil activation.& COPY; 2023 Elsevier Ltd. All rights reserved.