Sunday, October 16, 2022

Myocarditis Following COVID Infection and/or mRNA Vaccination (Revisited)




Credit ACIP/CDC

#17,066

Although most vaccines - including the COVID mRNA vaccines - have an enviable safety record, there is no such thing as a 100% safe drug or medication for 100% of the population. Even over-the-counter remedies, like NSAIDs or acetaminophen, can sometimes produce adverse - even fatal - reactions (see BMJ Research: NSAIDs & The Risk Of Heart Failure).

The decision to take any vaccine or medication always involves a risk-reward calculation. Most of the time, the small risk from a vaccine is justified, given the protection it provides.

Last week the State of Florida released new (and highly criticized) COVID Vaccine guidance (see State Surgeon General Dr. Joseph A. Ladapo Issues New Mrna COVID-19 Vaccine Guidance) advising males aged 18 to 39 against receiving mRNA COVID-19 vaccines, based on an in-house non-peer reviewed risk analysis by the Florida Department of Health. 

For a detailed dissection of Florida's guidance, you may wish to visit Florida’s COVID-19 Vaccination Analysis Is Flawed, Experts Say.

Leaving aside the merits (or lack, thereof) of the Florida's Surgeon General's controversial guidance, two facts are undisputed:

  1. Myocardititis has been reported in some (mostly young) recipients of the mRNA vaccine (see CDC Clinical Considerations : Myocarditis & Pericarditis after Receipt of mRNA COVID-19 Vaccines Among Adolescents and Young Adults)
  2. Myocardititis is a known complication of COVID infection (see Heart disease after COVID: what the data say) 
While this might seem like a damned if you do, and damned if you don't decision, there are studies showing that vaccine-induced myocarditis is generally milder than viral-induced myocarditis, and most people fully recover in 90 days or less. 

And while the distorting echo-chamber of social media may make vaccine-induced myocarditis seem like a common side effect of mRNA vaccination, the reality is less alarming. 

First stop, a preprint from Taiwan, showing  that myocarditis and pericarditis are rare following mRNA vaccination, albeit with a higher risk occurring in young males after the second dose, and concludes that "The benefits of COVID-19 vaccination far outweigh the possible harm for either the individual or society."

Risk of Myocarditis and Pericarditis Following Coronavirus Disease 2019 Messenger RNA Vaccination - A Nationwide Study
Wei-Ju Su, Yu-Lun Liu, Chia-Hsuin Chang, Yen-Ching Lin, Wei-I Huang, Li-Chiu Wu, Shu-Fong Chen, Yu-Sheng Lin, Yee-Lin Hsieh, Chiao-An Yang, Chiu-Hsiang Lin, Kim-Wei Arnold Chan, Ping-Ing Lee, Jen-Hsiang Chuang, Chin-Hui Yang
doi: https://doi.org/10.1101/2022.10.11.22280860
https://www.psu.edu/news/research/story/myocarditis-seven-times-more-likely-covid-19-vaccines/Background. An extended interval between the two primary doses may reduce the risk of myocarditis/pericarditis after COVID-19 mRNA vaccination. Taiwan has implemented a two-dose regimen with a 12-week interval for adolescents. Here we present nationwide data of mRNA COVID-19 vaccination-associated myocarditis and pericarditis in Taiwan.

Methods. Data on adverse events of myocarditis/pericarditis were from the Taiwan Vaccine Adverse Events Reporting System between March 22, 2021, and February 9, 2022. The rates according to sex, age, and vaccine type were calculated. We investigated the reporting rates among young individuals under different two-dose intervals and among those who received two doses of different vaccines.

Results. Among 204 cases who met the case definition of myocarditis/pericarditis, 75 cases occurred after the first dose and 129 after the second. The reporting rate of myocarditis/pericarditis after COVID-19 vaccination varied across sex and age groups and was highest after the second dose in males aged 12-17 years (126.79 cases per million vaccinees) for the BNT162b2 vaccine and in males aged 18-24 years (93.84 cases per million vaccinees) for the mRNA-1273 vaccine. The data did not suggest an association between longer between-dose interval and lower rate of myocarditis/pericarditis among males and females aged 18-24 or 25-29 years who received two doses of the BNT162b2 or mRNA-1273 vaccine. Rates of myocarditis/pericarditis in males and females aged 18-49 years after receiving ChAdOx1-S - mRNA-1273 vaccination was significantly higher than after ChAdOx1-S - ChAdOx1-S vaccination.

Conclusions. Myocarditis and pericarditis are rare following mRNA vaccination, with higher risk occurring in young males after the second dose.

Additionally, we've a recent study indicating that infection with the SARS-CoV-2 virus is far more likely to cause myocarditis than receipt of the vaccine.  Seven times more likely, according to an analysis by Penn State researchers. 

First some excerpts from a Penn State press release, then a link to their study.  
Myocarditis seven times more likely with COVID-19 than vaccines

OCTOBER 12, 2022

By Tracy Cox

HERSHEY, Pa. — The risk of developing myocarditis — or inflammation of the heart muscle — is seven times higher with a COVID-19 infection than with the COVID-19 vaccine, according to a recent study by Penn State College of Medicine scientists. Patients with myocarditis can experience chest pains, shortness of breath or an irregular heartbeat. In severe cases, the inflammation can lead to heart failure and death.

“Our findings show that the risk of myocarditis from being infected by COVID-19 is far greater than from getting the vaccine,” said Dr. Navya Voleti, a resident physician in the Department of Medicine at Penn State Health Milton S. Hershey Medical Center. “Moving forward, it will be important to monitor the potential long-term effects in those who develop myocarditis.”

Myocarditis is one of the complications of SARS-CoV-2 infection. Although vaccines have been shown to reduce severe COVID-19 symptoms, heart complications have been associated with mRNA COVID-19 vaccination — particularly myocarditis in teenage boys. However, the relative risk of myocarditis due to vaccines and infections had not been well characterized in large studies.
The Penn State team conducted the largest study to date on the risk of developing myocarditis as a result of having the coronavirus vs. experiencing inflammation following COVID-19 vaccination. The researchers compared patients with COVID-19 — vaccinated and unvaccinated — to those without the virus. They found the risk of myocarditis was 15 times higher in COVID-19 patients, regardless of vaccination status, compared to individuals who did not contract the virus.
Next, the researchers separately compared the rates of myocarditis in those who received the vaccines to those in unvaccinated individuals. According to the findings, the rates of myocarditis in people who were vaccinated against COVID-19 were only twofold higher than in unvaccinated people.

Based on all the findings, the researchers concluded that the risk of myocarditis due to COVID-19 was seven times higher than the risk related to the vaccines.

         (Continue . . . )


Myocarditis in SARS-CoV-2 infection vs. COVID-19 vaccination: A systematic review and meta-analysis

Navya Voleti1, Surya Prakash Reddy2 and Paddy Ssentongo1,3*


Were myocarditis the only adverse outcome of COVID infection, then perhaps a case might be made for recommending against mRNA vaccines for young, healthy, males. But COVID produces a wide range of serious, often long lasting sequelae, even in this cohort. 


A few (of many) blogs on this topic include:


While it may not seem like it if you - or someone you know - has an adverse reaction to the mRNA vaccine, the known risks from contracting COVID are demonstrably far greater.  

But we humans are a suspicious lot, and aren't very good at making risk-reward calculations.

So I don't expect these studies to change very many minds. 
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