Vaccines Associated Cardiac Adverse Events, Including SARS-Cov-2 Myocarditis, Elevated Histamine Etiology Hypothesis

Background: Rare cardiac adverse events are reported post vaccinations. For the SARS-CoV-2 mRNA Spike vaccines, higher numbers of these cardiac adverse events are being reported with myocarditis disproportionately occurring in younger males. The etiology of these cardiac adverse events associated with vaccines including SARS-CoV-2 is unknown. The etiology of the higher frequency of these cardiac adverse events temporally associated with SARS-CoV-2 mRNA Spike vaccines is also unknown. Aim: Data mine vaccine associated cardiac adverse events to gain insights into COVID-19 mRNA associated myocarditis and pericarditis adverse events. Methods: All adverse events, with a focus on cardiac adverse events, were summarized from the Vaccine Adverse Event Reporting System (VAERS) for all vaccines from 1990 to April 1, 2022. Results: Analogous patterns of cardiac adverse events were observed for multiple unrelated vaccines with occurrences proportional to vaccine reactogenicity level defined all adverse events. This article proposes the hypothesis that innate immune responses to vaccines cause elevated histamine levels post vaccination; the histamine level reached may exceed the vaccinees’ histamine tolerance level for several days, with the histamine level likely correlating with the vaccine reactogenicity level. Further, it is proposed that the elevated histamine level is causative for the reported cardiac adverse events. For myocarditis and pericarditis reported adverse events, the elevated histamine levels may induce cardiac capillary pericyte vasoconstrictions followed by localized ischemia and anoxia; this is followed by the release of troponin from myocyte cells affected by anoxia. This hypothesis is supported by the temporal onset timing of adverse events reported following SARS-CoV-2 mRNA Spike vaccinations in VAERS. Conclusion: Onset of cardiac adverse events immediately following vaccinations for multiple unrelated vaccines may implicate elevated histamine levels from immune responses as causative for these adverse events. Relevance for patients. An etiology model for cardiac adverse events temporally associated with vaccination is proposed. If validated, this model identifies possible candidate treatments for evaluation with the potential to reduce the severity and frequencies of these cardiac adverse events for vaccinees.