Editing Openai/6944461c-7f90-8000-8c32-54fe2958dd9a (section)

=== Assistant: Here’s the best available evidence on how the incidence of myocarditis a key serious adverse event after COVID-19 vacci… ===
Here’s the best available evidence on how the incidence of myocarditis (a key serious adverse event) after COVID-19 vaccination in U.S. military personnel compares to background (pre-COVID) rates — expressed in relative, percentage terms — based on published surveillance data:

===== A JAMA Cardiology analysis of U.S. Military Health System records reported: =====
* Observed myocarditis cases after COVID-19 mRNA vaccination: 19 among male service members who received 436 000 second doses.
* Expected myocarditis based on background rates: estimated 0–8 cases in that same subgroup.
'' That implies the observed number was ''higher than expected* relative to historical baseline. JAMA Network<ref>{{cite web|title=JAMA Network|url=https://jamanetwork.com/journals/jamacardiology/fullarticle/2781601|publisher=JAMA Network|access-date=2025-12-20}}</ref>

To approximate the relative change compared to expected background:
* Using the midpoint expected value (4 cases) vs observed (19): → [(19 − 4) / 4] × 100 ≈ +375% more cases than expected. This is an indicative relative increase (not exact incidence per person-year). JAMA Network<ref>{{cite web|title=JAMA Network|url=https://jamanetwork.com/journals/jamacardiology/fullarticle/2781601|publisher=JAMA Network|access-date=2025-12-20}}</ref>

Important nuance: this doesn’t mean all were caused by the vaccine — it means the number of cases was above baseline expectations given the size of the vaccinated population. JAMA Network<ref>{{cite web|title=JAMA Network|url=https://jamanetwork.com/journals/jamacardiology/fullarticle/2781601|publisher=JAMA Network|access-date=2025-12-20}}</ref>

===== A DoD report comparing myocarditis incidence before and after the vaccine requirement found: =====
* Crude myocarditis incidence after vaccination (within 21 days): ~40.6 per 100 000 person-years
* Crude myocarditis incidence without vaccination: ~17.1 per 100 000 person-years
* So the vaccinated group’s rate was ~2.4× higher — which is about a '''140% increase''' relative to the unvaccinated military baseline. Military Health System<ref>{{cite web|title=Military Health System|url=https://www.health.mil/Reference-Center/Reports/2023/09/29/DOD-Report-on-Cardiac-and-Kidney-Issues-in-Service-Members-Prior-to-and-Following-the-COVID-Vaccine-Requirement|publisher=Military Health System|date=2023-09-29|access-date=2025-12-20}}</ref>

===== For context (not military-specific numbers but relevant for interpretation): =====
* Myocarditis after SARS-CoV-2 infection was far more elevated (e.g., ~152.1 per 100 000 person-years) than after vaccination (~40.6 per 100 000 person-years) in the same DoD dataset — roughly ~10× higher with infection. Military Health System<ref>{{cite web|title=Military Health System|url=https://www.health.mil/Reference-Center/Reports/2023/09/29/DOD-Report-on-Cardiac-and-Kidney-Issues-in-Service-Members-Prior-to-and-Following-the-COVID-Vaccine-Requirement|publisher=Military Health System|date=2023-09-29|access-date=2025-12-20}}</ref>

===== 1. Different denominators & methods: Military analyses often compare expected based on background rates (historical) vs observed post-vaccine cases — not always clean case-control designs. =====
# Rare events: Even a 300–400% relative increase can reflect very small absolute numbers (dozens of cases per ~100 000 people).
# Causality ≠ incidence difference: Observed excess above historical expectation doesn’t by itself prove vaccination caused the increase; it flags a signal for further study.
# Infection effects dominate: COVID-19 infection itself carries a higher myocarditis risk, which complicates thinking about relative changes pre- vs post-pandemic and pre- vs post-vaccination.

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But in absolute terms this still represents a rare outcome (tens of cases per 100 000 person-years), and COVID-19 infection alone increases myocarditis risk far more in military populations than vaccination does. Military Health System<ref>{{cite web|title=Military Health System|url=https://www.health.mil/Reference-Center/Reports/2023/09/29/DOD-Report-on-Cardiac-and-Kidney-Issues-in-Service-Members-Prior-to-and-Following-the-COVID-Vaccine-Requirement|publisher=Military Health System|date=2023-09-29|access-date=2025-12-20}}</ref>

If you’d like, I can help you visualize these relative changes with a simple chart or translate this into a concise paragraph suitable for publication.