Covid-19 Vaccines and Myocarditis: Balancing Benefits and Risks in Adolescents and Young Adults

Two days ago the FDA indicated it will add a warning about rare cases of myocarditis in adolescents and young adults to information sheets for the Pfizer/BioNTech, and Moderna COVID-19 vaccines.

This followed a decision made by CDC advisor that myocarditis in adolescents and young adults is likely linked to the vaccines, but that the benefits of the vaccine ouweight the risks.

I think this is a reasonable approach to the problem: make doctors and patients aware of the issue, provide them with the best possible statistics and let them make the decision together.

The slides that the CDC advisory groups viewed are available online and they present an excellent and easily readable summary of the topic.

First we have a presentation on myocarditis in general and as it relates tothe mRNA COVID vaccines:

The incidence of myocarditis in 15 to 18 year olds in 2015-2016 was 1.8 cases per 100,000 individuals and 2/3 were male.

There are lots of different causes of myocarditis. For most patients a specific cause is not determined.

Benefit Versus Risk of Vaccination In the Young

Another presentation focused on the risk to benefit ratio of the mRNA vaccines and there is a wonderful slide deck available online and presented below

The slides show in detail by age group both the benefits of the vaccines (cases/hospitalization/ICU admissions/deaths prevented) and the presumed risk of myocarditis after first and second doses of the vaccine.

It is clear that individuals over the age of 29 years stand to benefit tremendously from vaccination with minimal risk.

Everyone in this age group should get vaccinated as soon as possible because COVID-19 is resurging and the vaccines protect against the delta variant which is leading the resurgence. My state, Missouri, I am sad to say, lead by southwest Missouri is leading the country in COVID resurgence as of this writing.

The benefit to risk ratio is lowest for second doses in males aged 12-17.

Young adults, aged 18-24 years show increased benefit compared to adolescents with decreased risk of myocarditis

There are additional considerations beyond myocarditis regarding benefits for individuals

And there are significant population-level benefits to consider:

The presentation concludes that benefits outweigh risk for COVID -19 vaccination in these younger age groups

Misinformation and the Vaccine Hesitant

I ask every patient I see in my office if they have received a COVID-19 vaccination. If they haven’t we have a discussion and I attempt to counter whatever misinformation is leading to their vaccine hesitancy.

Clearly, a lot of misinformation and propaganda is being circulated.

One patient told me that vaccines had caused 4000 deaths. This widespread fallacy is clearly false.

Another told me that the vaccines weren’t approved by the FDA. They are approved under an emergency use authorization and it is a foregone conclusion that they will receive full approval because large well-done randomized controlled clinical trials have demonstrated dramatic efficacy and safety.

Provaccinely Yours,



5 thoughts on “Covid-19 Vaccines and Myocarditis: Balancing Benefits and Risks in Adolescents and Young Adults”

  1. Dear Dr. Pearson,

    Since you’re a man of science and accordingly will appreciate the value of using precision in language I would like you to refer to the following passage from the FDA’s website. The passage describes how an EUA is not the same thing as an FDA approval.

    “Under section 564 of the Federal Food, Drug, and Cosmetic Act (FD&C Act), when the Secretary of HHS declares that an emergency use authorization is appropriate, FDA may authorize unapproved medical products or unapproved uses of approved medical products to be used in an emergency to diagnose, treat, or prevent serious or life-threatening diseases or conditions caused by CBRN threat agents when certain criteria are met, including there are no adequate, approved, and available alternatives.”

    • The FDA’s website also states

      Are the COVID-19 vaccines rigorously tested?

      Yes. Clinical trials are evaluating investigational COVID-19 vaccines in tens of thousands of study participants to generate the scientific data and other information needed by FDA to determine safety and effectiveness. These clinical trials are being conducted according to the rigorous standards set forth by the FDA.

      Initially, in phase 1, the vaccine is given to a small number of generally healthy people to assess its safety at increasing doses and to gain early information about how well the vaccine works to induce an immune response in people. In the absence of safety concerns from phase 1 studies, phase 2 studies include more people, where various dosages are tested on hundreds of people with typically varying health statuses and from different demographic groups, in randomized-controlled studies. These studies provide additional safety information on common short-term side effects and risks, examine the relationship between the dose administered and the immune response, and may provide initial information regarding the effectiveness of the vaccine. In phase 3, the vaccine is generally administered to thousands of people in randomized, controlled studies involving broad demographic groups (i.e., the population intended for use of the vaccine) and generates critical information on effectiveness and additional important safety data. This phase provides additional information about the immune response in people who receive the vaccine compared to those who receive a control, such as a placebo.

      What safety and effectiveness data are required to be submitted to FDA for an EUA request for a vaccine intended to prevent COVID-19?

      COVID-19 vaccines are undergoing a rigorous development process that includes tens of thousands of study participants to generate the needed non-clinical, clinical, and manufacturing data. FDA will undertake a comprehensive evaluation of this information submitted by a vaccine manufacturer.

      For an EUA to be issued for a vaccine, for which there is adequate manufacturing information to ensure quality and consistency, FDA must determine that the known and potential benefits outweigh the known and potential risks of the vaccine. An EUA request for a COVID-19 vaccine can be submitted to FDA based on a final analysis of a phase 3 clinical efficacy trial or an interim analysis of such trial, i.e., an analysis performed before the planned end of the trial once the data have met the pre-specified success criteria for the study’s primary efficacy endpoint.

      From a safety perspective, FDA expects an EUA submission will include all safety data accumulated from phase 1 and 2 studies conducted with the vaccine, with an expectation that phase 3 data will include a median follow-up of at least 2-months (meaning that at least half of vaccine recipients in phase 3 clinical trials have at least 2 months of follow-up) after completion of the full vaccination regimen. In addition, FDA expects that an EUA request will include a phase 3 safety database of well over 3,000 vaccine recipients, representing a high proportion of participants enrolled in the phase 3 study, who have been followed for serious adverse events and adverse events of special interest for at least one month after completion of the full vaccination regimen.

      Part of FDA’s evaluation of an EUA request for a COVID-19 vaccine includes evaluation of the chemistry, manufacturing, and controls information for the vaccine. Sufficient data should be submitted to ensure the quality and consistency of the vaccine product. FDA will use all available tools and information, including records reviews, site visits, and previous compliance history, to assess compliance with current good manufacturing practices.


  2. Thank you for this! Beautiful visualization of risks vs benefits. My father is quite taken by the misinformation on this one, with respect to us vaccinating our kids, so I have shared this for his peace of mind. (We’ve already vaccinated.) 5000 deaths he told me! Fox News. So dangerous. :( Anyhow, appreciate your blog.

  3. It might be too late to do test this, but from what I have read the second dose vaccine could theoretically be as useful at a drastically lower dosage.

    Also since myocarditis is a possible risk for such a short period of time, and one of the major risks of it is a fatal arrhythmia, wouldn’t it be prudent to have a warning to not exercise for 4 days or so post second vaccine? That way if there is transient myocarditis that is perhaps unnoticeable you’re at least not provoking it into something worse.

    • haven’t seen any reports of exercise induced fatal arrhythmias caused by vaccination. The myocarditis cases are quite mild and death from myocarditis would be a very rare occurence in general


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