PMID- 33807579 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20210413 IS - 2076-393X (Print) IS - 2076-393X (Electronic) IS - 2076-393X (Linking) VI - 9 IP - 3 DP - 2021 Mar 5 TI - Allergic Reactions to Current Available COVID-19 Vaccinations: Pathophysiology, Causality, and Therapeutic Considerations. LID - 10.3390/vaccines9030221 [doi] LID - 221 AB - Vaccines constitute the most effective medications in public health as they control and prevent the spread of infectious diseases and reduce mortality. Similar to other medications, allergic reactions can occur during vaccination. While most reactions are neither frequent nor serious, anaphylactic reactions are potentially life-threatening allergic reactions that are encountered rarely, but can cause serious complications. The allergic responses caused by vaccines can stem from activation of mast cells via Fcepsilon receptor-1 type I reaction, mediated by the interaction between immunoglobulin E (IgE) antibodies against a particular vaccine, and occur within minutes or up to four hours. The type IV allergic reactions initiate 48 h after vaccination and demonstrate their peak between 72 and 96 h. Non-IgE-mediated mast cell degranulation via activation of the complement system and via activation of the Mas-related G protein-coupled receptor X2 can also induce allergic reactions. Reactions are more often caused by inert substances, called excipients, which are added to vaccines to improve stability and absorption, increase solubility, influence palatability, or create a distinctive appearance, and not by the active vaccine itself. Polyethylene glycol, also known as macrogol, in the currently available Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines, and polysorbate 80, also known as Tween 80, in AstraZeneca and Johnson & Johnson COVID-19 vaccines, are excipients mostly incriminated for allergic reactions. This review will summarize the current state of knowledge of immediate and delayed allergic reactions in the currently available vaccines against COVID-19, together with the general and specific therapeutic considerations. These considerations include: The incidence of allergic reactions and deaths under investigation with the available vaccines, application of vaccination in patients with mast cell disease, patients who developed an allergy during the first dose, vasovagal symptoms masquerading as allergic reactions, the COVID-19 vaccination in pregnancy, deaths associated with COVID-19 vaccination, and questions arising in managing of this current ordeal. Careful vaccine-safety surveillance over time, in conjunction with the elucidation of mechanisms of adverse events across different COVID-19 vaccine platforms, will contribute to the development of a safe vaccine strategy. Allergists' expertise in proper diagnosis and treatment of allergic reactions is vital for the screening of high-risk individuals. FAU - Kounis, Nicholas G AU - Kounis NG AD - Department of Internal Medicine, Division of Cardiology, University of Patras Medical School, 26221 Patras, Greece. FAU - Koniari, Ioanna AU - Koniari I AD - Department of Internal Medicine, Division of Cardiology, University Hospital of South Manchester NHS Foundation Trust, Manchester M23 9LT, UK. FAU - de Gregorio, Cesare AU - de Gregorio C AUID- ORCID: 0000-0003-3022-266X AD - Department of Clinical and Experimental Medicine, University of Messina Medical School, 98122 Messina, Italy. FAU - Velissaris, Dimitris AU - Velissaris D AD - Department of Internal Medicine, University of Patras, 26500 Patras, Greece. FAU - Petalas, Konstantinos AU - Petalas K AUID- ORCID: 0000-0003-1680-3062 AD - Department of Allergology, 251 General Air Force Hospital, 11525 Athens, Greece. FAU - Brinia, Aikaterini AU - Brinia A AD - Allergy Practice, 26221 Patras, Greece. FAU - Assimakopoulos, Stelios F AU - Assimakopoulos SF AUID- ORCID: 0000-0002-6901-3681 AD - Department of Internal Medicine, Division of Infectious Diseases, University of Patras Medical School, 26500 Patras, Greece. FAU - Gogos, Christos AU - Gogos C AUID- ORCID: 0000-0002-9598-6954 AD - Covid-19 Unit, Papageorgiou General Hospital, 56403 Thessaloniki, Greece. FAU - Kouni, Sophia N AU - Kouni SN AD - Speech Therapy Practice, 26221 Patras, Greece. FAU - Kounis, George N AU - Kounis GN AD - Department of Ophthalmology, "Saint Andrews" State General Hospital, 26335 Patras, Greece. FAU - Calogiuri, GianFranco AU - Calogiuri G AD - Pneumonology Department, Civil Hospital "NinettoMelli", Pietro Vernoti, 72027 Brindisi, Italy. AD - Department of Internal Medicine, Immunology and Infectious Diseases, Section of Allergology and Clinical Immunology, University of Bari Medical School, 70121 Bari, Italy. FAU - Hung, Ming-Yow AU - Hung MY AUID- ORCID: 0000-0002-6912-7523 AD - Department of Internal Medicine, Division of Cardiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan. AD - Department of Internal Medicine, Division of Cardiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan. AD - Taipei Heart Institute, Taipei Medical University, Taipei 110, Taiwan. LA - eng PT - Journal Article PT - Review DEP - 20210305 PL - Switzerland TA - Vaccines (Basel) JT - Vaccines JID - 101629355 PMC - PMC7999280 OTO - NOTNLM OT - COVID-19 OT - Kounis syndrome OT - allergy OT - anaphylaxis OT - vaccines COIS- The authors declare that the review was conducted in the absence of anycommercial or financial relationships that could be construed as a potential conflict of interest. EDAT- 2021/04/04 06:00 MHDA- 2021/04/04 06:01 PMCR- 2021/03/05 CRDT- 2021/04/03 01:27 PHST- 2021/02/05 00:00 [received] PHST- 2021/02/22 00:00 [revised] PHST- 2021/02/25 00:00 [accepted] PHST- 2021/04/03 01:27 [entrez] PHST- 2021/04/04 06:00 [pubmed] PHST- 2021/04/04 06:01 [medline] PHST- 2021/03/05 00:00 [pmc-release] AID - vaccines9030221 [pii] AID - vaccines-09-00221 [pii] AID - 10.3390/vaccines9030221 [doi] PST - epublish SO - Vaccines (Basel). 2021 Mar 5;9(3):221. doi: 10.3390/vaccines9030221.