cdc.gov/coronavirus

mRNA COVID-19

Vaccine-Associated Myocarditis

Matthew Oster, MD, MPH

CDC COVID-19 Response, Vaccine Task Force

Pediatric Cardiologist, Children’s Healthcare of Atlanta
Outline

 Cases of myocarditis after COVID-19 vaccine

 Comparing types of myocarditis

 3-6 month outcomes of myocarditis
Vaccine Adverse Event Reporting System (VAERS):

Reporting rates (per 1 million doses administered) of myocarditis after 

mRNA COVID-19 vaccines, 7-day risk period

* An estimated 1–10 cases of myocarditis per 100,000 person years occurs among people in the United States, regardless of vaccination status; adjusted for the 7-

day risk period, this estimated background is 0.2 to 1.9 per 1 million person 7-day risk period 

3

Pfizer Pfizer

(Males) (Females)

Ages Dose 1 Dose 2 Dose 1 Dose 2

12-15 4.2 39.9 0.4 3.9

16-17 5.7 69.1 0.0 7.9

18-24 2.3 36.8 0.2 2.5

25-29 1.3 10.8 0.2 1.2

30-39 0.5 5.2 0.6 0.7

40-49 0.3 2.0 0.1 1.1

50-64 0.2 0.3 0.3 0.5

65+ 0.2 0.1 0.1 0.3

 Reporting rates exceed 

background incidence*
Care and outcomes of preliminary myocarditis cases reported to VAERS 

after mRNA COVID-19 vaccination in persons aged <30 years (N=1,640) 

(data thru Oct 6, 2021)

1,640 total preliminary reports

 877 met CDC case definition* 

of myocarditis 

 637 under review

Of 877 meeting case definition:

 829 were hospitalized 

• 789 discharged

‒ 607/789 (77%) known to 

have recovered from 

symptoms at time of report

 34 were not hospitalized (seen in 

emergency room, urgent care, 

outpatient clinic, not specified)

 Cardiac MRI abnormal in 72% of 

cases (223/312)

4

* Definition available from Gargano JW, Wallace M, Hadler SC, et al. Use 

of mRNA COVID-19 Vaccine After Reports of Myocarditis Among Vaccine 

Recipients: Update from the Advisory Committee on Immunization 

Practices — United States, June 2021. MMWR Morb Mortal Wkly Rep 

2021;70:977–982.

https://www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7027e2-H.pdf
Cases with concern 

for myocarditis

N=9

Information 

available

N=8

Evaluation ongoing

N=2

Evaluation 

complete

N=6

Not myocarditis

N=3

Myocarditis

N=3

Potential infectious 

cause identified

N=3

No other cause 

identified

N=0

Adequate 

information not 

available

N=1

Reports of deaths in persons aged <30 years with possible 

concern for myocarditis in VAERS (among ~86 million doses)
Comparing types of myocarditis

“Classic”

Myocarditis

MIS-C

Myocarditis

COVID-19 

Related 

Myocarditis

COVID-19 

Vaccine-Related 

Myocarditis
Causes of “classic” myocarditis
Epidemiology of myocarditis in pre-COVID era

 Children

• Annual incidence 0.8 per 100,000

• In persons aged 15-18 years, 1.8 per 

100,000 in 2015-2016

• 66% male

• Mortality 4-7%, transplant 4-9%

 Adults

• Gradual decrease in incidence with 

age

• 76% male

Vasudeva et al. American J Cardiology. 2021.

Kyto et al. Heart. 2013.

Ghelani et al. Circ Cardiovasc Qual Outcomes. 2012

Butts et al. Pediatric Cardiology. 2017

Sachdeva et al. Am J Cardiol.2015
MIS-C myocarditis

Belay et al. 2021 Feldstein et al. 2020
COVID-19 myocarditis among pediatric patients

Myocarditis Diagnosed (%) Myocarditis NOT Diagnosed (%)

COVID-19 (without MIS-C) 78 (0.02%) 356,721 (99.98%)

MIS-C 203 (8.10%) 2303 (91.90%)

Myocarditis Diagnosed (%) Myocarditis NOT Diagnosed (%)

COVID-19 (without MIS-C) 20 (0.08%) 24,144 (99.92%)

MIS-C 172 (9.04%) 1730 (90.96%)

https://www.epic.com/software#Cosmos https://www.childrenshospitals.org/phis
Comparing types of myocarditis

Patel et al. 2021
Patel et al. 2021

Troponin BNP Lymphocytes

White blood cells

C-reactive protein Platelets
Comparing Types of Myocarditis:

Time to Normal Ejection Fraction (EF) by Echocardiogram

Patel et al. 2021
Pre-COVID myocarditis outcomes

Picarillo et al. 2021
Picarillo et al. 2021
Picarillo et al. 2021

LGE=Late gadolinium enhancement
2015 Guidelines from American Heart Association and 

American College of Cardiology

Maron et al. JACC. 2015

Burns et al. J Peds X. 2020.
Vaccine Safety Datalink Confirmed Myocarditis/pericarditis 0-21 Days after Any Dose of mRNA 

Vaccine by Age Group/Product: 3 month follow-up review of Cases with at least 1 follow-up visit 

since initial episode

3-month chart review status

(not mutually exclusive)

12-17 Year-Olds 

(PfizerBioNTech)

N=16

18-39 Year-Olds

(PfizerBioNTech)

N=14

18-39 Year-Olds 

(Moderna)

N=18

Recovered, no medication, without exercise 

restrictions or symptoms 5 (31%) 6 (43%) 9 (50%)

Still symptomatic 4 (25%) 5 (36%) 3 (17%)

Still on medication (primarily NSAIDS, colchicine) 2 (13%) 4 (29%) 7 (39%)

Still on exercise/physical activity restrictions 7 (44%) 2 (14%) 1 (6%)
3-6 Month Outcomes of Myocarditis after COVID-19 

Vaccination

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myo-outcomes.html
20

Patient self-report of symptoms within prior 2 weeks at 3-month follow-up of myocarditis 

after COVID-19 vaccination (N=248)

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myo-outcomes.html

0 50 100 150 200

yes

no

yes

no

yes

no

yes

no

Chest pain SOB Palpitations Fatigue

Number of patients

Symptoms

71%

29%

74%

25%

76%

24%

76%

24%

Fatigue

Palpitations

Shortness of breath

Chest Pain

52% of patients 

reported no 

symptoms 

within prior 2 

weeks
21

Results of 3-month follow-up cardiac testing in patients with myocarditis 

after COVID-19 vaccination

0 10 20 30

Elevated

Normal

Abnormal

Normal

Abnormal

Normal

Abnormal

Boderline

Normal

Troponin MRI ECHO ECG

Number of patients

14%

3%

88%

12%

67%

33%

96%

4%

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myo-outcomes.html

83%

Electrocardiogram

Echocardiogram

Cardiac MRI

Troponin

N=29

N=25

N=15

N=25
Cardiologist/healthcare provider assessment of recovery from myocarditis 

after COVID-19 vaccination by 3 months (n=47) 

 91% of cardiologists or healthcare providers indicated the patient was fully or 

probably recovered

0

5

10

15

20

25

30

35

40

Same cardiac status

as at the initial

myocarditis diagnosis

Improved, but not

fully recovered

Probably fully

recovered, but

awaiting additional

information

Fully recovered

Number of Patients

Patient Recovery 74% 

17% 

6% 2% 

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myo-outcomes.html
For more information, contact CDC

1-800-CDC-INFO (232-4636)

TTY: 1-888-232-6348 www.cdc.gov

The findings and conclusions in this report are those of the authors and do not necessarily represent the 

official position of the Centers for Disease Control and Prevention.

Thank you

Acknowledgments:

• CDC COVID-19 Vaccine Task Force, Vaccine Safety Team

• Clinical Immunization Safety Assessment Project

• Tom Shimabukuro, John Su, CDC Vaccine Task Force

• Nicola Klein, Vaccine Safety Datalink

• Sam Butler, EPIC

• Matt Hall and Cary Thurm, Children’s Hospital Association

• CDC team investigating long-term effects of myocarditis