key: cord-0873054-28rjwxqf
authors: Pfaar, O; Mahler, V
title: Allergic reactions to COVID‐19 ‐vaccinations – unveiling the secret(s)
date: 2021-01-12
journal: Allergy
DOI: 10.1111/all.14734
sha: 47034bc23c4d94b74b99a725b580882623d59b9a
doc_id: 873054
cord_uid: 28rjwxqf

Since the beginning of the current pandemic our journal has published a series of important mechanistic and clinical reports of severe acute respiratory syndrome coronavirus type 2 (SARS‐CoV‐2) infection and Coronavirus Disease 2019 (COVID‐19) aimed to keep our readership up‐to‐date on all relevant developments in this world‐wide crisis (1). This issue of Allergy features articles with current information on allergy‐related questions regarding COVID‐19 vaccination.

This article is protected by copyright. All rights reserved conclude that the potential risk of PEG for sensitized patients should be further evaluated (6) . In a Correspondence to this, Krantz et al. summarize PEG and potentially cross-reactive polysorbate 80 as excipients in different therapeutics and extensively discuss IgE-mediated mechanisms causing anaphylactic reactions to PEG (7) . In addition, plausible mechanisms, such as complement activation, and molecular weight thresholds of PEG allergenicity are discussed. The authors recommend that patients with previous immediate reactions, such as PEG-induced anaphylaxis, vaccination with BNT162b2, further mRNA candidates and PEGylated products should be avoided until the individual risks are assessed by an allergist. Furthermore, the underlying mechanisms of these reactions triggered by mRNA vaccines should be better characterized. This important investigation is regarded as crucial for the development of mRNA vaccines in general, including those concerning other viruses and cancer (7).

In their reply to this Correspondence, Cabanillas et al. add that although there is a broad range of delivery routes for PEG and PEG-analogues (e.g., the skin, gastrointestinal mucosa, conjunctiva, intramuscularly, intravenously and others) and the immune system is regularly exposed to these excipients, allergic sensitizations are 

This article is protected by copyright. All rights reserved Immunology (EAACI) aims to provide preliminary recommendations on vaccination for COVID-19 based on current data from clinical (pivotal-)trials but also from international pharmacovigilance -reports after initiation of the mRNA vaccination program (10) . The Position Paper states that patients with mild and moderate allergies should not be excluded from vaccination programs as this may put population (herd-)immunity at risk due to the high prevalence of allergic diseases. There is a current need to improve our During the post-marketing authorization period, the regulatory agencies and the national competent authorities recommend further monitoring of hypersensitivity events. To identify the factors and risk groups for serious hypersensitivity reactions, it is of utmost importance to obtain detailed case-related information (11) through the European register for spontaneous reports and to apply the same criteria to describe anaphylactic reactions to vaccines. The World Health Organization and regulatory Accepted Article

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