Kounis syndrome must be considered in the differential diagnosis of myocardial infarction following COVID-19 vaccination.

Abstract

We read with interest the case series ‘A spectrum of cardiac manifestations post Pfizer-BioNTech coronavirus disease 2019 (COVID-19) vaccination’. 1 The authors described three interest-ing cases of myocardial injury that occurred following the first dose of the BNT162b1 mRNA COVID-19 vaccine (Pfizer, New York, NY, USA). The first and third cases are myocardial infarction that manifested 6 and 2 h after the vaccine dose administration, respectively. In the discussion of the cases, the authors state that the Pfizer-BioNTech vaccine trials did not show any serious complication or side effect, except for anaphylaxis, and also state that current literature has not demonstrated any association between COVID-19 vaccines and potential cardio-vascular complications. In view of this statement, we sought to add a comment. We want to emphasize that allergic reactions following COVID-19 vaccination can cause cardiac injury. There are mul-tiple reported cases of acute myocardial infarction occurring within minutes to hours after COVID-19 vaccine dose administration, some of which were associated with signs and symp-toms of anaphylaxis. 2–5 In an acute hypersensitivity reaction, activated mastocytes release allergic mediators, i.e. histamines, cytokines and tryptase. These mediators