Myocarditis following COVID-19 mRNA vaccination: a Nationwide issue and in our local area of Lee and Collier County

Views and opinions expressed are those of the authors and are not necessarily those of the Collier County Medical Society’s Board of Directors, staff, or advertisers. This article has not been part of a scholarly peer-review.

Jesus Mendiolaza MD, FACC, Board Certified Cardiologist, Internal Medicine and Nuclear Cardiology, Naples Cardiac and Endovascular Center

In December 2020, the Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for the Pfizer-BioNTech mRNA vaccine (BNT162b2) for prevention of COVID-19 disease. The vaccine’s EUA relied on data which were obtained from several clinical trials. The results of these trials revealed that the vaccine’s efficacy is 95% and its safety profile is good and similar to that of other vaccines. Systemic reactions to the vaccine, which were usually mild and transient, were reported more commonly among the younger population and more often after the second dose.

On May 24, 2021 the COVID-19 Vaccine Safety Technical (VaST) Work Group Report has reviewed post-authorization COVID-19 vaccine safety data weekly since the start of the U.S. vaccination program in December 2020, they reviewed updated data on myocarditis and pericarditis after COVID-19 vaccination, including presentations from the Vaccine Adverse Event Reporting System (VAERS) and the Vaccine Safety Datalink (VSD), along with a brief update from the Department of Veteran Affairs (VA) about further plans for investigation.

  • Data from VAERS show that in the 30-day window following dose 2 mRNA COVID-19 vaccination, there was a higher number of observed than expected myocarditis/pericarditis cases in 16- to 24-year-olds.
  • The CDC’s “clinical considerations” update followed a May 24 report from Advisory Committee on Immunization Practices (ACIP)’s COVID-19 VaST Work Group, which found “a higher number of observed than expected myocarditis/pericarditis cases in 16- to 24-year-olds” in VAERS data within 30 days of dose 2, though it didn’t see the same pattern in data from Vaccine Safety Datalink. Nonetheless, “analyses suggest that these data need to be carefully followed as more persons in younger age groups are vaccinated,” the work group wrote.

In early June, the CDC issued a note to healthcare providers raising awareness of myocarditis and pericarditis after vaccination, particularly in younger males. That guidance stated that, since April, there has been an increase in reports of myocarditis and pericarditis after getting the Pfizer or Moderna vaccines, but that there has not been a similar reporting pattern following the Johnson & Johnson vaccine.

Recently, the FDA at the advisory committee meeting, Tom Shimabukuro, MD, MPH, a member of the CDC COVID-19 vaccine task force, presented early data on the safety of the vaccines. In the VAERS database, there have been 475 cases of myocarditis and pericarditis in people ages 30 years and younger, of whom 226 met the CDC working case definition. Of the 285 cases with a known outcome, 270 patients were discharged and 81% made a full recovery. In those ages 16 to 17 years, there were 79 cases of myocarditis/pericarditis following 2.3 million administered mRNA vaccinations. The number of cases exceeds the cases expected in the general population ages 16 to 24 years.

CDC’s healthcare professional guidance notes that cases have occurred mainly in males ages 16 and up, and onset came within the first several days following vaccination, more often after the second dose.

Symptoms of myocarditis and pericarditis include chest pain, shortness of breath, or palpitations. In most cases, patients responded well to medications and rest, and their symptoms improved quickly, CDC said.

The agency has recommended an initial evaluation “considering an ECG, troponin level, and inflammatory markers such as C-reactive protein and erythrocyte sedimentation rate.”

It also said that for suspected cases, physicians should consider consulting with cardiology for help with evaluation and management.

Our experience in our local area:

Background: Clinical trials of the BNT162b2 vaccine, revealed efficacy and safety. We report 3 cases of myocarditis, which occurred shortly after BNT162b2 vaccination.

We are presenting you our recent experience (since May 14, 2021) of these first 4 patients who were identified upon presentation to the emergency department at our local hospital in Collier County with symptoms of chest pain/discomfort. In all 4 cases, I was consulted by the ED physicians due to patients presented with chest pain and troponin positive in one case (34-year-old female with supraventricular tachycardia and chest pain plus currently smoker). In all of them, we excluded past and current COVID-19. Routine clinical and laboratory investigations for common etiologies of myocarditis were performed. Laboratory tests also included troponin and C-reactive protein levels and ESR in conjunction with urine drug screen, (in one case pregnancy test) , EKG, pro BNP plus several different cardiac testing modalities: echocardiography, cardiac coronary CTA, cardiac catheterization and regretfully CARDIAC MRI was not obtained due to “insurance issues”. All of the aforementioned studies helped us to determine and established our clinical diagnosis as well corroborated by their response to our medical therapy installed immediately (3 of them received colchicine – males – and one just supportive medical therapy – female).

Findings: 3 patients presented after the second and one after the first dose of the vaccine. The 3 patients were males with a median age of 23 years, and one was a female of age 34. Myocarditis was diagnosed in all patients, there was no evidence of COVID-19 infection. Laboratory assays excluded concomitant infection; autoimmune disorder was considered unlikely. Their clinical course was mild in all 4 patients.

In one particular patient, the 20-year-old male, healthy adolescent, athletic individual, with no medical history, cardiac biomarkers including troponins went up to 33.6 ng/ml, when upon presenting to the ED with baseline of 24.2 ng/ml (of note normal levels in our local community hospital is less than 0.05 ng/ml), he was severely tachycardic (sinus tachycardia) moderately difficult to control initially and during his hospital stay, however upon the 3rd day of colchicine therapy plus appropriate supportive medical therapy (beta blockers), he responded gradually well and in addition the biomarkers as well, being discharged a week after initial presentation.

All echo reports in our series of patients were normal, with no structural heart disease, and in just one case (female case) she underwent cardiac catheterization due to her history of new onset supraventricular tachycardia with heart rate up to 175 bpm and responded to adenosine, and heavy smoker with normal coronary arteries.

All their electrocardiograms were showing NO ischemic changes, imaging appropriately followed, and one case underwent CARDIAC coronary CTA with normal findings.

In 3 of our cases, they responded very well to colchicine therapy and in one case (the female) “just supportive” therapy provided due to her own request.

All of them were discharged in stable condition and have resumed their normal activities


Our report of myocarditis after BNT162b2 vaccination may be possibly considered as an adverse reaction following immunization. We believe our information should be interpreted with caution and further surveillance is warranted.

Health federal agencies also are emphasizing that the benefits of vaccination outweigh risks at this point.