Vaccine-associated hypersensitivity

Information for Category 1 CME CreditCredit can now be obtained, free for a limited time, by reading the review articles in this issue. Please note the following instructions.Method of Physician Participation in Learning Process: The core material for these activities can be read in this issue of the Journal or online at the JACI Web site: www.jacionline.org. The accompanying tests may only be submitted online at www.jacionline.org. Fax or other copies will not be accepted.Date of Original Release: February 2018. Credit may be obtained for these courses until January 31, 2019.Copyright Statement: Copyright © 2018-2019. All rights reserved.Overall Purpose/Goal: To provide excellent reviews on key aspects of allergic disease to those who research, treat, or manage allergic disease.Target Audience: Physicians and researchers within the field of allergic disease.Accreditation/Provider Statements and Credit Designation: The American Academy of Allergy, Asthma & Immunology (AAAAI) is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians. The AAAAI designates this journal-based CME activity for a maximum of 1.00 AMA PRA Category 1 Credit™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.List of Design Committee Members: Michael M. McNeil, MD, MPH, and Frank DeStefano, MD, MPH (authors); Zuhair K. Ballas, MD (editor)Disclosure of Significant Relationships with Relevant CommercialCompanies/Organizations: The authors declare that they have no relevant conflicts of interest. Z. K. Ballas (editor) disclosed no relevant financial relationships.Activity Objectives:1.To be able to discuss the differences in underlying mechanisms and presentation of immediate and delayed vaccine reactions.2.To be aware of the most recent vaccine guidelines regarding patients with egg allergy and influenza vaccination.3.To understand the limited data supporting other components of vaccines that might be implicated as possible causes of anaphylaxis.4.To be able to discuss the rate and clinical risk factors for vaccine-triggered anaphylaxis.Recognition of Commercial Support: This CME activity has not received external commercial support.List of CME Exam Authors: Daniel Har, MD, Shyam Joshi, MD, Mariam Wahidi, MD, Shazia Lutfeali, MD, and David A. Khan, MD.Disclosure of Significant Relationships with Relevant CommercialCompanies/Organizations: The exam authors disclosed no relevant financial relationships.Vaccine-associated hypersensitivity reactions are not infrequent; however, serious acute-onset, presumably IgE-mediated or IgG and complement-mediated anaphylactic or serious delayed-onset T cell-mediated systemic reactions are considered extremely rare. Hypersensitivity can occur because of either the active vaccine component (antigen) or one of the other components. Postvaccination acute-onset hypersensitivity reactions include self-limited localized adverse events and, rarely, systemic reactions ranging from urticaria/angioedema to full-blown anaphylaxis with multisystem involvement. Risk of anaphylaxis after all vaccines is estimated to be 1.31 (95% CI, 0.90-1.84) per million vaccine doses, respectively. Serious hypersensitivity reactions after influenza vaccines are particularly important because of the large number of persons vaccinated annually. Influenza vaccines are unique in requiring annual changes in the vaccines' antigenic composition to match the predicted circulating influenza strains. Recently, novel influenza vaccine types were introduced in the United States (recombinant vaccines, some with higher antigen content and a new adjuvanted vaccine). Providers should be aware of changing recommendations on the basis of recent published evidence for persons with a history of egg allergy to receive annual influenza vaccination. Further research is needed to elucidate the pathophysiology and risk factors for reported vaccine-associated adverse events. Further research is also needed to determine whether repeated annual inactivated influenza vaccination, the number of vaccine antigens administered at the same time, and the current timing of routine infant vaccinations are optimal for overall population well-being.