InpharmD™

What do case reports say about the incidence of myocarditis following mRNA COVID-19 vaccination in adults and adolescent males?

Comment by InpharmD Researcher

There may be a possibility of an association between mRNA COVID-19 vaccination and acute myocarditis. However, the data presented in the case reports is not definitive. Overall, incidence rate of myocarditis and myopericarditis after COVID-19 mRNA vaccination cannot be accurately determined. Given that further studies are needed for strong, conclusive evidence, it is encouraged for patients to get the vaccination as benefits may outweigh risk.

Background

Since April 2021, increased cases of myocarditis and pericarditis have been reported in the United States after mRNA COVID-19 vaccination (Pfizer-BioNTech and Moderna), particularly in adolescents and young adults. There has not been a similar reporting pattern observed after receipt of the Janssen COVID-19 Vaccine (Johnson & Johnson). [1]

In most cases, patients who presented for medical care have responded well to medications and rest and had prompt improvement of symptoms. Reported cases have occurred predominantly in male adolescents and young adults 16 years of age and older. Onset was typically within several days after mRNA COVID-19 vaccination, and cases have occurred more often after the second dose than the first dose. CDC and its partners are investigating these reports of myocarditis and pericarditis following mRNA COVID-19 vaccination. The CDC continues to recommend COVID-19 vaccination for everyone 12 years of age and older given. [1]

The Centers for Disease Control and Prevention (CDC) states, "cases of myocarditis and pericarditis in adolescents and young adults have been reported more often after getting the second dose than after the first dose of one of these two mRNA COVID-19 vaccines. These reports are rare and the known and potential benefits of COVID-19 vaccination outweigh the known and potential risks, including the possible risk of myocarditis or pericarditis." [2]

On June 23rd, 2021, the following statement was co-signed by the U.S. Department of Health and Human Services (HHS), Centers for Disease Control and Prevention (CDC), American Academy of Family Physicians (AAFP), American Academy of Pediatrics (AAP), American College of Obstetricians and Gynecologists (ACOG), American College of Physicians (ACP), American Heart Association, American Hospital Association (AHA), American Medical Association (AMA), American Nurses Association (ANA), American Public Health Association (APHA), Association of Public Health Laboratories, Association of State and Territorial Health Officials (ASTHO), Big Cities Health Coalition, Council of State and Territorial Epidemiologists, Infectious Diseases Society of America, and National Association of County and City Health Officials (NACCHO):

“The facts are clear: this is an extremely rare side effect, and only an exceedingly small number of people will experience it after vaccination. Importantly, for the young people who do [become infected], most cases are mild, and individuals recover often on their own or with minimal treatment. In addition, we know that myocarditis and pericarditis are much more common if you get COVID-19, and the risks to the heart from COVID-19 infection can be more severe.” [3]

According to the new update from the Advisory Committee on Immunization Practices (ACIP) published earlier July 9, 2021, the panel has noticed an elevated risk of myocarditis, particularly among males aged 12-29 years after receiving mRNA COVID-19 vaccines. After reviewing reported cases of myocarditis and pericarditis, on June 23, 2021, ACIP states the benefits of receiving mRNA COVID-19 vaccines apparently outweigh the risks in adolescents and young adults. Accordingly, the Emergency Use Authorization (EUA) also reflects the information on myocarditis for public awareness. [4]

Among patients <30 years with reported myocarditis during May 1 – June 11, 2021, 323 of the 484 cases were determined to meet CDC's criteria of myocarditis, pericarditis, or myopericarditis based on provider interview and chart-review of the medical records. The median age of these confirmed cases was 19 (range, 12−29), and 291 (90.1%) of them were male. From vaccination to symptom onset, the median interval was two days (range, 0-40 days), and 309 (96%) were hospitalized for further management. By the time of case review, 95% of the patients had been discharged after mainly receiving conservative treatment, such as nonsteroidal anti-inflammatory drugs. Continuous follow-up is warranted to investigate long-term effects of myocarditis after receiving COVID-19 vaccines. Utilizing VAERS data with onset within seven days after dose 2 of an mRNA vaccine administered to males 12-29 years old, myocarditis reporting rates were 40.6 cases per million. The reporting rate was 62.8 myocarditis cases per million-second doses of mRNA COVID-19 vaccine administered among adolescents aged 12−17. In conclusion, ACIP emphasized the benefits over risks in this particular patient population, and the need to monitor and disseminate the information among the public and providers. [4]

Per the vaccine adverse effects reporting system (VAERS) database on July 27th, 2021, there have been 351 reports of myocarditis in pediatric patients. The majority have been associated with Pfizer (n = 347). [5]

The rate of myocarditis after the vaccination is potentially lower than in children who become infected. A cross‐sectional study included all children ≤18 years diagnosed with microbiologically confirmed (PCR analysis on nasopharyngeal swab) COVID‐19 (through a nasopharyngeal swab from March 2020 to October 2020; N= 129; mean age of 11 ± 4.4 years, 62 (48.1%) female). During the acute COVID‐19, 33 children (25.6%) were asymptomatic, and 96 (74.4%) had symptoms. Overall, 6 (4.7%) children were hospitalized, and 3 (2.3%) needed pediatric intensive care unit admission. After the initial diagnosis of COVID‐19, three developed multisystem inflammatory syndrome (2.3%) and two myocarditis (1.6%). [6]

Literature Review

A search of the published medical literature revealed 4 studies investigating the researchable question:

What do case reports say about the incidence of myocarditis following mRNA COVID-19 vaccination in adults and adolescent males?

Please see Tables 1-4 for your response.

Patients With Acute Myocarditis Following mRNA COVID-19 Vaccination
Design	Case report
Case Presentation	Characteristics of Patients Who Received COVID-19 Vaccination
	Characteristics	Patient 1	Patient 2	Patient 3	Patient 4
	Age, years	36	23	70	24
	Sex	Male	Male	Female	Male
	Comorbidities Hypertension Diabetes Hypercholesterolemia Cigarette smoking History of CAD or MI Prior myocarditis Prior COVID-19 infection	No No No No No No No	No No No No No No No	Yes No Yes Yes No No No	No No No No No No No
	Vaccine received Doses received	mRNA-1273 2	BNT162b2 2	mRNA-1273 2	BNT162b2 2
	Symptoms prior to vaccination (last dose) Viral prodrome
	Symptoms within 24 h of vaccination Injection site discomfort Fatigue/muscle ache Fever/chills Headache Nausea Chest pain	Yes Yes Yes No No No	Yes Yes Yes No No No	No No No No No Yes	Yes Yes Yes Yes No No
	Hospitalization Interval after vaccination, days	3	5	1	2
	Symptoms leading to hospitalization Severe chest pain (<12 h of hospitalization) Shortness of breath Diaphoresis Syncope/presyncope Palpitations	Yes Yes No No No	Yes Yes No Yes No	Yes Yes Yes No No	Yes No No No Yes
	Severe chest pain	Yes	Yes	Yes	Yes
	In-hospital testing
	Electrocardiogram	Diffuse ST elevation; PR depression	Lateral; ST elevation	Anterolateral; ST elevation	Diffuse ST elevation: PR depression
	Peak troponin, ng/L	hs-Tn T: 230 (abnormal)	hs-Tn I: 7452 (abnormal)	Tn I: 2.34 (abnormal)	hs-Tn T: 698 (abnormal)
	CPR, mg/dL ESR, mm/h ProBNP, pg/mL WBC, /uL COVID-19 testing Respiratory virus PCR Chest radiography Chest CT Coronary angiography	6.32 (abnormal) 6 NP 10,200 Negative Negative Normal Negative for PE NP	2.2 (abnormal) 30 (abnormal) 780 (abnormal) 10,800 Negative Negative Normal Negative for PE NP	Not performed (NP) NP 5,194 (abnormal) 16,700 (abnormal) NP NP Normal NP Normal coronaries	6.08 (abnormal) 12 65 13,500 (abnormal) Negative NP Normal NP NP
	Cardiac MRI Interval after vaccination, days LVEF,% Regional wall motion abnormality Pericardial effusion Pericardial thickness	3 53 Yes Trace Normal	5 58 Yes Small Normal	3 40 Yes Small Normal	3 59 Yes Trace Normal
	LEG present Location Myocardial pattern Pericardial enhancement	Yes Apical lateral Epicardial No	Yes Multiple Epicardial No	Yes Multiple Patchy, diffuse No	Yes Lateral Epicardial, patchy No
	Therapy Corticosteroids Colchicine NSAIDs	No Yes Yes	Yes Yes No	No No No	No Yes Yes
	Abbreviations: CAD, coronary artery disease; CRP, C-reactive protein; CT, computed tomography; ESR, erythrocyte sedimentation rate; hs-Tn, high-sensitivity troponin; LGE, late gadolinium enhancement; LVEF, left ventricular ejection fraction; MI myocardial infarction; MRI, magnetic resonance imaging; NSAIDs, nonsteroidal anti-inflammatory drugs; PCR, polymerase chain reaction; PE, pulmonary emboli; proBNP, pro-brain-type natriuretic peptide; WBC, whit blood cell count
Study Author Conclusions	In this study of 7 identified patients with acute myocarditis, 4 occurred within 5 days of COVID-19 vaccination between February 1 and April 30, 2021. All 4 patients had received the second dose of a messenger RNA (mRNA) vaccine, presented with severe chest pain, had biomarker evidence of myocardial injury, were hospitalized, and had cardiac magnetic resonance imaging findings typical of myocarditis. Several caveats should be considered. First, there is no control group, and it is not possible to compare rates of acute myocarditis between those randomly assigned to receive vaccination vs no vaccination. Second, given the media attention, there could be recall or referral bias after COVID-19 vaccination compared with other vaccine exposures, and any temporal link between vaccination and myocarditis could just be due to chance. Third, although tests for COVID-19 infection and respiratory viruses were undertaken in some of the patients, these tests are neither foolproof nor comprehensive. Finally, there is no serological data, which could provide evidence of an excessive response to vaccination or prior subclinical COVID-19 infection (as determined by antinucleocapsid antibodies). The findings from the present report raise the possibility of an association between mRNA COVID-19 vaccination and acute myocarditis.

References:

Kim HW, Jenista ER, Wendell DC, et al. Patients with acute myocarditis following mRNA COVID-19 vaccination. JAMA Cardiol. 2021:e212828. doi: 10.1001/jamacardio.2021.2828.

Symptomatic Acute Myocarditis in 7 Adolescents After Pfizer-BioNTech COVID-19 Vaccination
Design	Case report
Case Presentation	Demographic and Clinical Characteristics of 7 Cases of Symptomatic Myocarditis After Dose 2 of Pfizer-BioNTech COVID-19 Vaccine
		Patient 1	Patient 2	Patient 3	Patient 4	Patient 5	Patient 6	Patient 7
	Age, years	16	19	17	18	17	16	14
	Sex	Male	Male	Male	Male	Male	Male	Male
	Race	White	White	White	White	White	White	White
	Weight, kg	68	68	71	69	64	71	92
	Exposure to COVID-19 in 14 d before illness onset	None	None	None	None	None	None	None
	Time between vaccine dose 2 and symptoms onset, days	2	3	2	2	4	3	2
	Total hospital LOS, days	6	2	2	4	5	3	4
	ICU LOS, days	4	None	None	4	5	2	2
	Symptoms on presentation
	Chest pain	Present	Present	Present	Present	Present	Present	Present
	Other pain	Bilateral arm pain	Myalgia	Bilateral arm pain, numbness, paresthesia	--	Bilateral arm pain, abdominal pain	--	--
	Fever	38.3C by history	Subjective, chills	--	Subjective	Subjective	--	38.3C by history
	Fatigue	Present	Present	--	Present	--	--	--
	Other	Nausea, vomiting, anorexia, headache	Weakness	--	Nausea	Nausea, vomiting, anorexia, SOB, palpitations	SOB	SOB
	Summary of Diagnostics and Therapeutics: 7 Cases of Symptomatic Myocarditis After Dose 2 of Pfizer-BioNTech COVID-19 Vaccine
	Laboratory findings on admission:
	Troponin (normal range), ng/mL	Troponin I: 2.59 (<0.03)	High-sensitivity troponin T: 232 (<14)	Troponin I: 5.55 (<0.045)	Troponin T:1.09 (<0.01)	Troponin T: 3.2 (<0.01)	Troponin T: 0.66 (<0.01)	Troponin I: 22.1 (<0.045)
	Brain natriuretic peptide (normal < 100), pg/mL	--	--	--	--	--	--	107.9
	NT-proBNP (normal <125), pg/mL	428	--	376	--	978	149	--
	Peripheral white blood cell count, thousands of cells per mm³	6.97	8.69	11.8	12.6	16.3	5.0	8.11
	Absolute lymphocyte count, thousands of cells per mm³	1.69	1.39	2.13	2.3	4.1	1.4	1.05
	Absolute neutrophil count, thousands of cells per mm³	4.65	5.93	7.46	9.5	9.8	2.8	4.73
	Platelet count, thousands of cells per mm³	198	208	231	236	297	189	208
	Albumin (g/dL)	3.9	4.1	4.1	4.4	4.0	3.8	3.5
	Aspartate transaminase, U/L	54	29	41	82	150	59	87
	Alanine transaminase, U/	30	14	33	20	46	22	38
	Ferritin, ug/L	70	--	90	103	347	65	84
	CRP (normal <1.0), mg/dL	0.99	6.7	2.5	12.7	18.1	1.5	7.7
	ESR, mm/h	18	13	6	40	38	3	10
	Prothrombin time, seconds	--	--	14.0	--	12.1	11.4	14.8
	Partial thromboplastin time, seconds	22.3	--	31.4	--	30.4	27.9	35.6
	International normalized ratio INR	1.11	--	1.06	--	1.13	1.06	1.2
	Other pertinent laboratory findings:
	Highest troponin (normal range), ng/mL	Troponin I: 12.43 (<0.80)	High-sensitivity troponin T: 388 (<14)	Troponin I: 12.20 (<0.045)	Troponin T: 1.09 (<0.01)	Troponin T: 3.33 (<0.01)	Troponin T: 0.82 (<0.01)	Troponin I: 22.1 (<0.045)
	Lowest troponin before discharge (normal range), ng/mL	Troponin I: 1.42(<0.80)	--	Troponin I: 5.79 (<0.045	Troponin T: 0.4 (<0.01)	Troponin T: 0.96 (<0.01)	Troponin T: 0.01 (<0.01)	Troponin I: 8.02 (<0.045)
	Highest BNP (normal range), pg/mL	--	--	--	--	--	--	205 (<100)
	Highest NT-proBNP (normal range)	482 pg/mL (<125)	--	376 pg/mL (<300)	--	978 pg/mL (<125)	275 pg/mL (<125)	--
	Highest CRP (normal <1.0), mg/dL	1.23	6.7	2.53	12.7	18.1	1.8	12.7
	COVID-19 PCR result	Negative	Negative	Negative	Negative	Negative	Negative	Negative
	COVID-19 spike antibody (manufacturer)	--	--	Positive (Roche)	Positive (Roche)	Positive (Roche)	Positive (Roche)	--
	COVID-19 nucleocapsid antibody result (manufacturer)	Negative (Abbott)	--	Negative (Roche)	Negative (Roche)	Negative (Roche)	Negative (Roche)	Negative (Abbott)
	Respiratory pathogen panel PCR result (manufacturer)	Negative (BioFire)	Negative (BioFire)	Negative (BioFire)	Negative (BioFire)	Negative (BioFire)	Negative (BioFire)	Negative (BioFire)
	Adenovirus diagnostics result	Negative serum PCR	--	Negative serology	Negative serum PCR	Negative serum PCR	--	Negative serum PCR
	Enterovirus diagnostics result	Negative serum PCR	--	Negative serology	Negative serum PCR	Negative serum PCR	Negative serum PCR	Negative serum PCR
	Cytomegalovirus diagnostics result	Negative serum PCR	--	Negative serology	Negative serum PCR	Negative serum PCR	Negative serum PCR	Negative serology
	Epstein-Barr virus diagnostics result			Negative serology	Negative serum PCR	Negative serum PCR	Negative IgM, positive IgG antibody	Negative serology
	Other diagnostics			Negative parvovirus, bartonella, and Lyme serology, negative urine drug screen	--	Negative parvovirus and bartonella serology, negative HHV-6 serum PCR	Negative Lyme serology, negative mycoplasma serum PCR, negative parvovirus serum PCR	Negative parvovirus IgM, positive parvovirus IgG antibody, negative mycoplasma PCR (throat swab)
	Diagnostic imaging findings:
	Cardiac MRI	LGE (subepicardial) involving lateral LV apex, myocardial edema of lateral LV wall, left axillary adenopathy	LGE involving mid LV wall, myocardial edema of basal inferolateral LV wall	LGE (subepicardial) involving basal anterolateral and basal to midventricular inferolateral LV segments, myocardial edema, elevated extracellular volume fraction (29.2%)	Fibrosis, myocardial edema, hyperemia, mild mitral regurgitation (RF ∼18%)	LGE (epicardial) involving anterior and lateral LV wall, no myocardial edema	LGE, diffuse myocardial edema	LGE (subepicardial) involving mid and apical LV free wall, myocardial edema, hyperemia
	Echocardiogram	Normal	Normal	Borderline basal lateral and basal posterior strain	Normal	Normal	Normal	Mildly depressed RV and LV systolic function (LVEF 47%)
	ECG	Atrioventricular dissociation with junctional escape rhythm, ST elevation	ST segment elevation (diffuse)	ST elevation (diffuse), T-wave abnormality	ST elevation	Sinus bradycardia, T-wave abnormality	ST elevation (diffuse)	ST elevation, low voltage of extremity leads
	Therapeutics:
	Oxygen supplementation	None	None	None	None	None	None	LFNC
	Vasoactive medications or inotropic support	None	None	None	None	None	None	None
	Antiinflammatory agents and other relevant medications	NSAID, IVIg, IV methylprednisolone, PO prednisone, famotidine	NSAID, colchicine, aspirin	NSAID, famotidine	NSAID, IVIg, IV methylprednisolone, PO prednisone	NSAID, IVIg, IV methylprednisolone, PO prednisone, aspirin	IVIg, PO prednisone	NSAID, famotidine, furosemide
	Abbreviations: HHV-6, human herpesvirus-6; IgG, immunoglobulin G; IgM, immunoglobulin M; INR, international normalized ratio; IV, intravenous; LGE, late gadolinium enhancement; LFNC, low flow nasal cannula; LV, left ventricular; LVEF, left ventricular ejection fraction; PO, per os (oral); q12hr, every 12 hours; RF, regurgitant fraction; RV, right ventricular; —, not done.
Study Author Conclusions	Our case series has inherent limitations. We compiled cases through personal communications among colleagues rather than using a systematic surveillance system to identify cases. It was not possible to exclude all alternative etiologies including idiopathic and other infectious etiologies, and there was not a systematic diagnostic evaluation for other viral etiologies. Cardiac biopsy was not performed on any patients because they were all clinically stable during hospitalization. However, no patient had evidence of a preceding or concurrent symptomatic viral illness to implicate as an etiology of myocarditis, and the lack of eosinophilia dissuades a hypersensitivity reaction. The pathophysiology of myocarditis in these patients is indeterminate, and we do not know if it is the same or different from classic myopericarditis or myopericarditis after other vaccines, associated with acute COVID-19, or with MIS-C. Given the nature of a case series, we cannot determine the incidence rate of myocarditis and myopericarditis after COVID-19 mRNA vaccination. Finally, a negative nucleocapsid antibody test result does not conclusively rule out the possibility of natural infection. A series of U.S. cases of myocarditis and myopericarditis in adolescent male individuals occurred after the second dose of the Pfizer-BioNTech COVID-19 mRNA vaccine. Fortunately, none of our patients was critically ill and each was discharged from the hospital. At present, there is no definite causal relationship between these cases and vaccine administration.

References:

Marshall M, Ferguson ID, Lewis P, et al. Symptomatic acute myocarditis in 7 adolescents after Pfizer-BioNTech COVID-19 vaccination. Pediatrics. 2021;148(3):e2021052478. doi:10.1542/peds.2021-052478.

COVID-19 Vaccine and Myocarditis
Design	Pooled analysis of case series and case reports (till June 27, 2021)
Case Presentation	Characteristics and outcomes of patients with myocarditis related to COVID-19 vaccine
		Age	Sex	Type of vaccine	Dose	Peak cardiac troponin I (ng/mL)	Peak cardiac troponin T (ng/mL)	LVEF (%)	Time to resolution (days)
	1	25	M	Moderna	2nd	20.4	-	55%	3
	2	21	F	Moderna	2nd	4.4	-	50%	1
	3	17	M	Pfizer-BioNTech	1st	51.37	-	53%	6
	4	28	M	J&J	N/A	17.08	-	50%	2
	5	39	M	Moderna	2nd	11.01	-	56%	4
	6	39	M	Pfizer-BioNTech	2nd	13	-	52%	3
	7	24	M	Pfizer-BioNTech	1st	0.37	-	48%	2
	8	19	M	Pfizer-BioNTech	2nd	4.49	-	50%	3
	9	20	M	Pfizer-BioNTech	2nd	0.48	-	52%	4
	10	23	M	Pfizer-BioNTech	2nd	7	-	50%	2
	11	52	M	Moderna	2nd	6.77	-	54%	4
	12	16	M	Pfizer-BioNTech	2nd	12.56	1693	61%	6
	13	30	M	Pfizer-BioNTech	2nd	18.94	-	"normal"	Resolved (duration not reported)
	14	24	M	Moderna	2nd	-	-	65%	Resolved (duration not reported)
	15	39	M	Pfizer-BioNTech	1st	-	854	"normal"	6
	M =male; F =female; LVEF =left ventricular ejection fraction
Study Author Conclusions	This pooled analysis of the available data shows several important findings: First, myocarditis related to COVID-19 vaccines mostly occurs in young male individuals following the second dose of the vaccine. Second, myocarditis related to COVID vaccines mostly occurs with mRNA vaccines (ie, Pfizer-BioNTech and Moderna COVID-19 vaccines). Third, in all the reported cases of myocarditis related to COVID-19 vaccine, clinical symptoms resolved within 6 days with preservation of the cardiac function. Third, no complications were reported in any of these patients. This analysis shows that myocarditis related to COVID-19 vaccine has an overall fast recovery with no short-term complications.

References:

Salah HM, Mehta JL. COVID-19 vaccine and myocarditis. Am J Cardiol. 2021:S0002-9149(21)00639-1. doi: 10.1016/j.amjcard.2021.07.009.

Association of Myocarditis with BNT162b2 Messenger RNA COVID-19 Vaccine in a Case Series of Children
Design	Case series (N=15)
Case Presentation	Characteristics of Patients with Myocarditis after COVID-19 Vaccine
	Characteristic	At time of admission	Outpatient follow-up
	Age, years	15 (12 to 18)	NA
	Male	14 (93%)	NA
	Onset of symptom after vaccine, days	3 (1 to 6)	NA
	Race/ethnicity Non-Hispanic White Hispanic White Other Hispanic Other non-Hispanic Unknown	8 (53%) 2 (15) 1 (8%) 1 (8%) 3 (20%)	NA NA NA NA NA
	Day at follow-up, days	NA	6 (1 to 13)
	Duration of symptoms, days	3 (1 to 9)	NA
	Chest pain Fever Myalgia Headache Fatigue	15 (100%) 10 (67%) 8 (53%) 6 (40%) 6 (40%)	1 (7%) 0 (0%) 0 (0%) 0 (0%) 3 (20%)
	Duration of hospitalization, days	2 (1 to 5)	NA
	Immunomodulatory treatment	7 (47%)	7 (47%)
	Laboratory values Troponin level, ng/mL (normal ≤0.01) BNP, pg/mL (normal <10) CRP, mg/dL (normal ≤0.50)	0.25 (0.08 to 3.15) 22 (10 to 184) 3.01 (0.69 to 10.00)	0.01 (0.01 to 0.16) 12 (10 to 64) 0.24 (0.03 to 0.86)
	ECG Diffuse ST-segment elevation T-wave inversion	9 (60%) 0 (0%)	6 (40%) 3 (30%)
	Echocardiogram Ejection fraction, % Circumferential strain, % Circumferential strain z score Longitudinal strain, % Longitudinal strain z score Septal e', cm/s Septal e' z score Septal E/e' ratio Septal E/e' ratio z score Lateral e', cm/s Lateral e' z score Lateral E/e' ratio Lateral E/e' ratio z score	58.6 (43.7 to 64.7) -23.4 (-34.2 to -15.3) -1.8 (-4.0 to 1.1) -19.2 (-26.8 to -11.1) -0.9 (-3.3 to 1.8) 12.6 (11.0 to 18.2) -0.5 (-1.3 to 2.2) 6.9 (5.0 to 8.4) -0.1 (-1.2 to 0.9) 15.3 (11.1 to 22.7) -1.3 (-2.7 to 1.3) 5.9 (3.0 to 7.6) 0.5 (-1.4 to 1.7)	59.3 (54.4 to 71.5) -28.8 (-35.0 to -23.2) -0.3 (-1.9 to 1.4) -20.7 (-24.4 to -15.1) -0.3 (-2.0 to 1.0) 13.0 (9.4 to 18.4) -0.4 (-2.0 to 2.2) 7.9 (4.1 to 10.1) 0.6 (-1.8 to 1.9) 16.9 (10.4 to 25.6) -0.7 (-2.8 to 2.3) 5.7 (3.4 to 9.2) 0.4 (-1.2 to 2.6)
	Cardiac MRI Time from onset of symptoms, days Regional hyperintensity on T2-weighted imaging Extracellular volume fraction, % LV global T2, ms LV global native T1, ms Late gadolinium enhancement	3 (1 to 7) 2 (13%) 27 (22 to 37) 51.5 (47.0 to 57.6) 1048 (963 to 1121) 12 (80%)	NA NA NA NA NA NA
	Data are presented in median (range). Abbreviations: BNP, brain natriuretic peptide; CRP, C-reactive protein; e', early diastolic tissue Doppler velocity; E, mitral inflow early diastolic pulsed-Doppler velocity; ECG, electrocardiogram; LV: left ventricular; MRI, magnetic resonance imaging; T2, transverse relaxation time; T1, longitudinal relaxation time.
Study Author Conclusions	In this case series of 15 children who were hospitalized with myocarditis after receipt of the BNT162b2 messenger RNA COVID-19 vaccine for 1 to 5 days, boys were most often affected after the second vaccine dose, 3 patients had ventricular systolic dysfunction, and 12 patients had late gadolinium enhancement on cardiac magnetic resonance imaging. There was no mortality, and all but 1 patient had normal echocardiogram results on follow-up 1 to 13 days after discharge. To date (July 20, 2021- accepted for publication), there have been 1,226 reports of myocarditis after messenger RNA vaccination to the Vaccine Adverse Event Reporting System (VAERS), including 687 in persons aged less than 30 years. Crude reporting rates using vaccine administration data estimates the highest rate among male individuals aged 12 to 17 years (62.8 cases per million), similar to our observations. Despite the risks of myocarditis associated with vaccination, the benefits of vaccination likely outweigh risks in children and adolescents. It is estimated that COVID-19 vaccination in males aged 12 to 29 years can prevent 11 ,000 COVID-19 cases, 560 hospitalizations, 138 intensive care unit admissions, and 6 deaths compared with 39 to 47 expected myocarditis cases.

References:

Dionne A, Sperotto F, Chamberlain S, et al. Association of myocarditis with BNT162b2 messenger RNA COVID-19 vaccine in a case series of children. JAMA Cardiol. 2021:e213471. doi: 10.1001/jamacardio.2021.3471.