Thread by @GidMK

I think the vaccine/COVID myocarditis issue in kids really shows the difference between those reasonably weighing up costs and benefits and those who are either dishonest or not very good at epidemiology 1/n

2/n We know two things with a great deal of certainty for younger people:

1. myocarditis following vaccination is rare
2. myocarditis following COVID-19 is rare

3/n This is probably not a surprise, because myocarditis is rare in younger people regardless of the situation. Here's a study that found an incidence of 2 cases per 100,000 kids each year ncbi.nlm.nih.gov/pmc/articles/P…

4/n Now, the issue is, we aren't quite sure which of these rare events (vaccine or COVID-induced myocarditis) is more common. Some studies say COVID, some indicate the vaccine (particularly Moderna)

5/n And, if we were totally incompetent, we might argue that, since some studies observe myocarditis at a slightly higher rate in younger people after vaccination, this means that the vaccine is causing harm

But that's a very bad argument

6/n Why? Well, while myocarditis is the main serious issue identified in young people post-vaccine, COVID-19 causes any number of serious, harmful problems

7/n Just look at the Nature Medicine paper that has sparked so much of this nonsense. Myocarditis in people <40 years is higher with Moderna than the virus!

8/n Except, look at pericarditis and arrythmias. Basically no risk from the vaccines, HUGE increased risk from the virus (the graphs are only for all ages, but from the supplement the virus increases the risk of arrythmias by >30x in under 40s)

9/n And those are just cardiac complications! If we take the gold standard of dividing hospitalizations by number of infections based on serology, COVID-19 causes hospitalization for about 1 in 1,000 children. WAY higher than the vaccine medrxiv.org/content/10.110…

9.5/n On top of this, we've got the risks from long COVID. One study found that 1 in 5 adolescents report anosmia 3 months after COVID infection (this may be inflated by various biases, but is still something to consider) researchsquare.com/article/rs-798…

10/n Now, it's true that we don't know what the marginal benefit of second/third doses is on reducing these higher risks from COVID vs the increased risk from some vaccines of myocarditis

11/n This is a complex question that almost certainly has a complex answer, and I can see why some people have recommended against boosters for teen boys in this context

12/n That being said, if someone presents only the risk of myocarditis for COVID-19 vs vaccines, it's just a poorly-done piece of work that doesn't address the issues we care about much, if at all

13/n (It should be noted that this is NOT a criticism of the Nature Med paper, which didn't actually make this claim because they seem to be quite good at epidemiology and weighing risks and benefits)

14/n It's been pointed out that I should've been more clear - yes, the primary risk is for young men aged 11-29 receiving their 2nd dose of mRNA vaccines, and this is where most of the complexity I alluded to above lies

https://twitter.com/AngryCardio/status/1483978105089933312?s=20

15/n Current evidence appears to indicate that the risk for younger children is negligible, and girls are also at a much lower risk at all ages cdc.gov/mmwr/volumes/7…