Burgeoning Evidence of Myopericarditis After Covid-19 Vaccination in Young People: A Call For Acknowledgment, Pause, and Serious Study

The Vaccine Adverse Event Reporting System [VAERS] (1) is a passive or “spontaneous” Centers For Disease Control and Prevention [CDC] and U.S. Food and Drug Administration [FDA] vaccine safety and monitoring system (2). Designed primarily for “safety signal detection,” VAERS describes potential associations between vaccine administration and adverse events, “hypothesis generation,” that could merit formal investigation (2). A recent example, which appears increasingly germane to covid-19 vaccination, in particular, with mRNA covid-19 vaccines available in the U.S. [i.e., from Pfizer and Moderna] (3), was the relationship between smallpox vaccination and the development of myopericarditis in military personnel, especially young men (4-8). Although not “hypothesis generating,” per se, a subsequent VAERS analysis (7), utilizing influenza vaccination (and other vaccinations) as a control, independently validated the association between smallpox vaccination and myopericarditis, as well as the lack of association, described earlier (8), with influenza vaccination. Granted understandable caveats about attributing “causality” to VAERS adverse events associations with vaccination (1,2), if anything, the system chronically under reports adverse events of possible interest (9).

With this background in mind, I applied the “preferred term” myocarditis/myopericarditis VAERS search strategy described by Su et al (7) for all vaccines,1990-2018, to the past 6-month experience with all covid-19 vaccines, only. Su et al tallied 705 VAERS case reports of myopericarditis over their designated 28-year time period. The identical VAERS search strategy applied to covid-19 vaccines administered in just the past 6-months [through 6/20/21] yielded 1160 cases of myopericarditis.

Apropos to heightened concerns about myopericarditis in those under 30-years of age following covid-19 mRNA vaccination (3), especially after the second dose, I also performed a subsequent VAERS analysis [6/21/21] of the limited available echocardiographic data from 496 VAERS cases in this young age group. Decreased ejection fraction—a marker of global left ventricular function (i.e., cardiac “pump” function)—is a demonstrated predictor of major adverse cardiac events following a bout of myocarditis (10,11).   Notwithstanding rather glib assertions that post-covid-19 vaccination myopericarditis is a benign phenomenon among those under 30-years old (12), 52/496, or 10.5% of these VAERS cases, reported “decreased ejection fractions.”

Immediately, this summer, controlled one-month longitudinal studies [see for example, ref. 8] of the incidence of myopericarditis should be conducted comparing covid-19 vaccinated and unvaccinated groups under 30-years of age, who undergo serial echocardiography, electrocardiography, and studies of blood cardiac injury markers [notably, troponin]. Pending completion of these studies, and rapid analyses of the data, there should be a moratorium on mass covid-19 vaccination of healthy, extraordinarily low covid-19 risk persons (13) less than 30-years old.


  1. Vaccine Adverse Event Reporting System, https://wonder.cdc.gov/vaers.html
  2. Shimabukuro TT, Nguyen M, Martin D, DeStefano F. “Safety monitoring in the Vaccine Adverse Event Reporting System (VAERS). Vaccine”. 2015 Aug 26;33(36):4398-405. doi: 10.1016/j.vaccine.2015.07.035. Epub 2015 Jul 22. PMID: 26209838; PMCID: PMC4632204
  3. “Vaccines and Related Biological Products Advisory Committee.” June 10, 2021 Meeting Presentation. https://www.fda.gov/media/150054/download
  4. Halsell JS, Riddle JR, Atwood JE, Gardner P, Shope R, Poland GA, Gray GC, Ostroff S, Eckart RE, Hospenthal DR, Gibson RL, Grabenstein JD, Arness MK, Tornberg DN; Department of Defense Smallpox Vaccination Clinical Evaluation Team. “Myopericarditis following smallpox vaccination among vaccinia-naive US military personnel”. JAMA. 2003 Jun 25;289(24):3283-9. doi: 10.1001/jama.289.24.3283. PMID: 12824210.
  5. Morgan J, Roper MH, Sperling L, Schieber RA, Heffelfinger JD, Casey CG, Miller JW, Santibanez S, Herwaldt B, Hightower P, Moro PL, Hibbs BF, Levine NH, Chapman LE, Iskander J, Lane JM, Wharton M, Mootrey GT, Swerdlow DL. “Myocarditis, pericarditis, and dilated cardiomyopathy after smallpox vaccination among civilians in the United States.” January-October 2003. Clin Infect Dis. 2008 Mar 15;46 Suppl 3:S242-50. doi: 10.1086/524747. PMID: 18284365.
  6. Poland GA, Grabenstein JD, Neff JM. “The US smallpox vaccination program: a review of a large modern era smallpox vaccination implementation program.” Vaccine. 2005 Mar 18;23(17-18):2078-81. doi: 10.1016/j.vaccine.2005.01.012. PMID: 15755574.
  7. Su JR, McNeil MM, Welsh KJ, Marquez PL, Ng C, Yan M, Cano MV. “Myopericarditis after vaccination, Vaccine Adverse Event Reporting System (VAERS), 1990-2018.” Vaccine. 2021 Jan 29;39(5):839-845. doi: 10.1016/j.vaccine.2020.12.046. Epub 2021 Jan 6. PMID: 33422381.
  8. Engler RJ, Nelson MR, Collins LC Jr, Spooner C, Hemann BA, Gibbs BT, Atwood JE, Howard RS, Chang AS, Cruser DL, Gates DG, Vernalis MN, Lengkeek MS, McClenathan BM, Jaffe AS, Cooper LT, Black S, Carlson C, Wilson C, Davis RL. “A prospective study of the incidence of myocarditis/pericarditis and new onset cardiac symptoms following smallpox and influenza vaccination.” PLoS One. 2015 Mar 20;10(3):e0118283. doi: .1371/journal.pone.0118283. PMID: 25793705; PMCID: PMC4368609.
  9. Baker MA, Kaelber DC, Bar-Shain DS, et al. “Advanced Clinical Decision Support for Vaccine Adverse Event Detection and Reporting”. Clin Infect Dis. 2015;61(6):864-870. doi:10.1093/cid/civ430.
  10. Wong BTW, Christiansen JP. Clinical Characteristics and Prognostic Factors of Myocarditis in New Zealand Patients. Heart Lung Circ. 2020 Aug;29(8):1139-1145. doi: 10.1016/j.hlc.2020.01.007. Epub 2020 Feb 17. PMID: 32094080.
  11. Ammirati E, Cipriani M, Moro C, Raineri C, Pini D, Sormani P, Mantovani R, Varrenti M, Pedrotti P, Conca C, Mafrici A, Grosu A, Briguglia D, Guglielmetto S, Perego GB, Colombo S, Caico SI, Giannattasio C, Maestroni A, Carubelli V, Metra M, Lombardi C, Campodonico J, Agostoni P, Peretto G, Scelsi L, Turco A, Di Tano G, Campana C, Belloni A, Morandi F, Mortara A, Cirò A, Senni M, Gavazzi A, Frigerio M, Oliva F, Camici PG; Registro Lombardo delle Miocarditi. Clinical Presentation and Outcome in a Contemporary Cohort of Patients With Acute Myocarditis: Multicenter Lombardy Registry. Circulation. 2018 Sep 11;138(11):1088-1099. doi: 10.1161/CIRCULATIONAHA.118.035319. PMID: 29764898.
  12. “Doctors looking into rare cases of myocarditis after mRNA vaccinations”, CTV News [Canada], June 18, 2021 https://www.ctvnews.ca/health/coronavirus/doctors-looking-into-rare-cases-of-myocarditis-after-mrna-vaccinations-1.5475636
  13. Ioannidis JPA. Reconciling estimates of global spread and infection fatality rates of COVID-19: An overview of systematic evaluations. Eur J Clin Invest. 2021 May;51(5):e13554. doi: 10.1111/eci.13554. Epub 2021 Apr 9. PMID: 33768536.

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