key: cord-0721523-1kg9j42f authors: Rosman, Yossi; Lavi, Noa; Meir-Shafrir, Keren; Lachover-Roth, Idit; Cohen-Engler, Anat; Mekori, Yoseph A.; Confino-Cohen, Ronit title: Safety of BNT162b2 mRNA COVID-19 vaccine in patients with mast cell disorders date: 2021-07-02 journal: J Allergy Clin Immunol Pract DOI: 10.1016/j.jaip.2021.06.032 sha: 845f73e5628185d4d9e99655f43d86f374cfe7f9 doc_id: 721523 cord_uid: 1kg9j42f nan progresses rapidly and might lead to death. It requires prompt recognition and treatment with epinephrine. In 38 anaphylaxis, serum tryptase level (STL) is typically elevated above normal levels (above 1.2 times baseline + 2 39 ng/ml), a feature that identifies MC as the sources of inflammatory mediators. Patients with MCD have increased risk for anaphylaxis due to various triggers including hymenoptera sting, 41 alcoholic beverages, contrast media, latex and drugs (1) . Vaccines have also been reported as the cause of 42 immediate reaction in patients with MCD (2). The first vaccine to receive authorization for emergency use in humans for prevention of the coronavirus was 44 the BNT162b2 mRNA COVID-19 vaccine (Pfizer-BioNTech, PBTV). Due to some early reports of allergic 45 reactions to the vaccine in the UK and USA (3, 4) , concern has been raised regarding the safety of this vaccine 46 for patients with risk for immediate allergic reactions in general and specifically for patients with MCD (5,6). To date, consistent data on the need and type of preventive measures in patients with MCD receiving COVID-48 19 vaccines are still lacking. The objective of this study was to evaluate the safety of the PBTV in patients with MCD. All participants received two injections of 30 µg of PBTV (0.3 ml volume per dose), delivered into the deltoid 56 muscle, 21 days apart. Vaccination was done in the allergy and clinical immunology unit at the Meir medical center. Serum tryptase 58 level was measured before and 90 minutes after vaccination by the ImmunoCAP method (Phadia 100 system: Phadia-Thermo Scientific, Waltham, Mass). Patients remained under observation for four hours after injection 60 and were discharged after an immediate allergic reaction was ruled out by an allergy specialist. Data were entered and tabulated using Excel 2007. Data are presented as mean and standard error (SE) for 62 continuous variables. Comparisons between groups were performed with Student's t test. All tests of hypotheses 63 were considered significant when two-sided probability values were P <0.05. Twenty-six adult patients with MCD that were vaccinated with the PBTV were included in our study. Demographic and clinical data are summarized in table 1. The vaccine was well tolerated by all patients (table 2) . Two patients (7.7%) suffered from mild symptoms after 67 the first injection. Both patients were observed, and no specific treatment was delivered besides paracetamol. All patients received the second dose, with no adverse events. Serum tryptase levels before and 90 minutes after 69 the injection were available in 14 patients (54%). No significant difference was found between STL before and In the past year, the coronavirus pandemic had a huge impact on the world. mRNA based vaccines are 74 considered as one of the major measures aimed to control this pandemic. Although these vaccines are 75 considered to be safe, concern has been raised regarding their potential to induce anaphylactic reactions (7). mRNA vaccines to patients with MCD. The ACAAI statement regarding mRNA vaccines stated that data 84 related to risk in individuals with MCAS is extremely limited and evolving. Excluding an encouraging case 85 report, no data exist regarding the actual risk of immediate allergic reactions to this vaccine, in patients with 86 MCD. In this work, we have demonstrated, for the first time, that the PBTV is safe and tolerable in patients with MCD, 88 regardless to the specific MCD or to documented past anaphylactic reactions. Although available in only half of 89 our patients, the fact that STL was not increased after vaccination, suggests that MC are not activated by the 90 vaccine. The fact that this population can be safely treated with PBTV is especially important considering the 91 potential to a more severe covid-19 respiratory disease in these patients (9). Most patients in our study were regularly treated with AH. Treatment was continued as usual before the 93 injection. We do not know whether the use of preventive AH lowered the risk for anaphylaxis, but it is worthy 94 to notice that the minority of patients that were not on regular AH treatment received the PBTV uneventfully as 95 well. The small cohort limits this study. However, MCD are rare; thus uneventful vaccination in 26 patients is 97 significant. Our patients were observed by an allergy specialist through the vaccination, and we have tested the 98 change in STL after injection in more than half of the subjects, reducing the risk for misdiagnosis. In conclusion, we found that the PBTV is safe and well tolerated in patients with MCD and can be administered Mast cells, mastocytosis, and related disorders children and adults with mastocytosis Reports of Anaphylaxis After Receipt of mRNA Maintaining Safety with SARS-CoV-2 Vaccines Delving Into COVID-19 Vaccination-Induced Anaphylaxis: Are 114 mRNA Vaccines Safe in Mast Cell Disorders? reactions after COVID-19 vaccination with the Pfizer/BioNTech vaccine in Great Britain