Post-Vaccination Myocarditis

A few Rose Cottage Doc followers have recently contacted me after having new onset chest pain after a mRNA vaccine. Whilst I endorse vaccination against Covid-19 I thought I should share recent changes in prescribing information for health care professionals.

If you have new onset chest pain, breathlessness or palpitations after your vaccine please see a health care provider. Maybe take this post with you.

Information taken from a piece written by Chloe Harman on the 28 June 2021 called "Myocarditis warning for Pfizer and Moderna COVID-19 vaccines" for health care professionals.

"The prescribing information for the Pfizer/BioNTech and Moderna COVID-19 vaccines has been updated following very rare reports of myocarditis and pericarditis.

Healthcare professionals should be alert to the signs and symptoms of myocarditis and pericarditis in patients given the Pfizer/BioNTech or Moderna COVID-19 vaccines, the MHRA has advised.

Patients should be advised to seek immediate medical attention should they experience new onset of chest pain, shortness of breath or symptoms of arrhythmia after receiving either of the mRNA vaccines, the MHRA (Medicines & Healthcare products

Regulatory Agency) says"

Yellow card reports

As of 16 June 2021, the MHRA had received 87 Yellow Card reports of myocarditis and pericarditis as suspected side-effects after administration of the Pfizer/BioNTech COVID-19 vaccine and 4 reports after the Moderna COVID-19 vaccine. Up to the same date an estimated 16.8 million first doses and 10.9 million second doses of the Pfizer/BioNTech vaccine had been administered, and an approximate 0.73 million first doses of the Moderna jab have also now been given.

*Rose Cottage Doc* a yellow card is used to report suspected side effects to medicines and vaccines or medical device and diagnostic adverse incidents used in coronavirus treatment.

Similar cases have also been reported internationally following receipt of the Pfizer/BioNTech and Moderna vaccines. These have occurred most frequently in younger males aged 40 years and younger and within 10 days after the second dose.

Most of these cases were mild and individuals typically recovered within a short time and with symptomatic treatment and rest.

Although reports of myocarditis and pericarditis after vaccination with the AstraZeneca COVID-19 vaccine have been received, the MHRA says there is insufficient evidence to recommend similar warnings for this vaccine.

Diagnosis of myocarditis and pericarditis typically requires targeted procedures such as electrocardiograms, cardiac imaging, and biomarker analysis and it is also important to exclude other potential causes for the symptoms, says the MHRA. Treatment of more symptomatic patients will occasionally require relevant expert follow up that might need detailed cardiac imaging to determine the nature of the condition".

In a paper by Rosner et al in Circulation 16 June 2021 entitled "COVID-19: postvaccine myocarditis symptoms resolve"

Takeaway message

  • For people who develop myocarditis after COVID-19 vaccination, the findings of this case series suggest that symptoms resolve.

Why this matters

  • The authors say that the risk-benefit decision continues to favour vaccination.

  • In a statement, the American Heart Association “continues to urge all adults and children ages 12 and older” to be vaccinated as soon as possible, per CDC recommendations.

Key results

  • All 7 patients were male; age, <40 years; White or Hispanic.

  • 6 had mRNA vaccine; 1 had adenovirus-vectored vaccine.

  • 1 had a history of COVID-19.

  • Presentation was acute-onset chest pain 3-7 days after vaccination and elevated troponin.

  • ECG was normal or showed ST segment elevation.

  • No pericardial friction rub, rash.

  • On angiography, no coronary artery disease obstruction found.

  • Left ventricular ejection fraction ranged from 35% to 62%.

  • Myocardial edema was found in 3 of 7.

  • No palpitations, evidence of sustained arrhythmia.

  • Treatment: beta-blockers, anti-inflammatories.

  • Hospital length of stay averaged 3 days.

  • All symptoms resolved at discharge.

Study design

  • Case series, 7 patients hospitalized in 2 centers for acute myocarditis-like illness after COVID-19 vaccination.

  • Funding: None specific to this study.


  • Small case series.

From these types of studies @dear_pandemic has created this helpful graphic:

The vaccine benefits are:

  • death prevention

  • prevention of hospitalization

  • prevention of an ICU admission / ventilation

  • potential prevention Long Covid

  • potential prevention MIS-C - Multiple System Inflammatory Syndrome in children

Bottom line:

  • Currently the benefits of vaccination outweigh the risks for young adults

  • There will need to be continued monitoring of cases, clinical course and long term outcomes of myocarditis after mRNA vaccines via the Yellow Card system

  • If you have new onset chest pain, breathlessness or palpitations after your vaccine please see a health care provider.


Myocarditis warning for Pfizer and Moderna COVID-19 vaccines

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