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This guidance updates 2021 GRADE (Grading of Recommendations Assessment, Development and Evaluation) recommendations regarding immediate allergic reactions following coronavirus disease 2019 (COVID-19) vaccines and addresses revaccinating individuals with first-dose allergic reactions and allergy testing to determine revaccination outcomes. Recent meta-analyses assessed the incidence of severe allergic reactions to initial COVID-19 vaccination, risk of mRNA-COVID-19 revaccination after an initial reaction, and diagnostic accuracy of COVID-19 vaccine and vaccine excipient testing in predicting reactions. GRADE methods informed rating the certainty of evidence and strength of recommendations. A modified Delphi panel consisting of experts in allergy, anaphylaxis, vaccinology, infectious diseases, emergency medicine, and primary care from Australia, Canada, Europe, Japan, South Africa, the United Kingdom, and the United States formed the recommendations. We recommend vaccination for persons without COVID-19 vaccine excipient allergy and revaccination after a prior immediate allergic reaction. We suggest against >15-minute postvaccination observation. We recommend against mRNA vaccine or excipient skin testing to predict outcomes. We suggest revaccination of persons with an immediate allergic reaction to the mRNA vaccine or excipients be performed by a person with vaccine allergy expertise in a properly equipped setting. We suggest against premedication, split-dosing, or special precautions because of a comorbid allergic history., (Crown Copyright © 2023. Published by Elsevier Inc. All rights reserved.)

Background: Berotralstat (BCX7353) is an oral, once-daily inhibitor of plasma kallikrein in development for the prophylaxis of hereditary angioedema (HAE) attacks., Objective: Our aim was to determine the efficacy, safety, and tolerability of berotralstat in patients with HAE over a 24-week treatment period (the phase 3 APeX-2 trial)., Methods: APeX-2 was a double-blind, parallel-group study that randomized patients at 40 sites in 11 countries 1:1:1 to receive once-daily berotralstat in a dose of 110 mg or 150 mg or placebo (Clinicaltrials.gov identifier NCT03485911). Patients aged 12 years or older with HAE due to C1 inhibitor deficiency and at least 2 investigator-confirmed HAE attacks in the first 56 days of a prospective run-in period were eligible. The primary efficacy end point was the rate of investigator-confirmed HAE attacks during the 24-week treatment period., Results: A total of 121 patients were randomized; 120 of them received at least 1 dose of the study drug (n = 41, 40, and 39 in the 110-mg dose of berotralstat, 150-mg of dose berotralstat, and placebo groups, respectively). Berotralstat demonstrated a significant reduction in attack rate at both 110 mg (1.65 attacks per month; P = .024) and 150 mg (1.31 attacks per month; P < .001) relative to placebo (2.35 attacks per month). The most frequent treatment-emergent adverse events that occurred more with berotralstat than with placebo were abdominal pain, vomiting, diarrhea, and back pain. No drug-related serious treatment-emergent adverse events occurred., Conclusion: Both the 110-mg and 150-mg doses of berotralstat reduced HAE attack rates compared with placebo and were safe and generally well tolerated. The most favorable benefit-to-risk profile was observed at a dose of 150 mg per day., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Because influenza vaccine contains some residual egg protein, there is a theoretic risk of anaphylaxis when vaccinating patients with egg allergy. The objective of this study was to estimate the risk of anaphylaxis in children with egg allergy administered an adjuvanted monovalent 2009 pandemic influenza A/H1N1 influenza vaccine (Arepanrix; GlaxoSmithKline, Mississauga, Ontario, Canada)., Methods: Patients with confirmed egg allergy with a history of respiratory or cardiovascular reactions after egg ingestion were vaccinated in 2 divided doses (10% and 90%) administered at a 30-minute interval, whereas children with other types of egg-induced allergic reactions were vaccinated with a single dose. All patients remained under observation for 60 minutes after vaccination. A 24-hour follow-up telephone call was made to detect any delayed reaction. The main outcome was the occurrence of an anaphylactic reaction according to criteria specified by the Brighton Collaboration., Results: Among the 830 patients with confirmed egg allergy, only 9% required the vaccine to be administered in divided doses. No patient had an anaphylactic reaction. Nine patients had minor allergic symptoms treated with an antihistamine (1 in the 60 minutes after vaccination and 8 in the following 23 hours), and 3 others received salbutamol (1 in the first 60 minutes after vaccination). Further vaccination of more than 3600 other children with reported egg allergy caused no anaphylaxis based on the criteria of the Brighton Collaboration, although 2 patients received epinephrine for symptoms compatible with allergy., Conclusion: Although anaphylaxis after influenza immunization is a theoretic risk, vaccination of patients with egg allergy with an adjuvanted monovalent pH1N1 influenza vaccine resulted in no cases of anaphylaxis and on that basis appears safe., (Copyright 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)