Myocarditis complications more common after Covid infection than vaccination | Hacker News Reader

Myocarditis complications more common after Covid infection than vaccination

cidrap.umn.edu

47 pointsripjaygn10 comments

"Participants had postvaccination myocarditis (within 1 week of COVID-19 mRNA vaccination; 588 patients [12%]), post-COVID myocarditis (within 30 days of infection; 298 [6%]), or conventional myocarditis (3,779 [82%]). The team also compared medical management in the three groups after hospital release."

OK, did they get something mixed up in the article?

I really want to criticize them for having a 30 day window for the infection but a 7 day window for vaccine reaction, but I'm not sure the information is accurate.

As if they were looking for some increase over time that never came from the infection side of the analysis, but after 7 days the vaccine data showed enough to make a solid point. But, I agree, just keeping them both at 30 days would have been easier to digest.

They are not talking about incidences, just the complications.

From the study:

> In total, 4635 individuals were hospitalized for myocarditis: 558 with postvaccine myocarditis, 298 with post–COVID-19 myocarditis, and 3779 with conventional myocarditis. Patients with postvaccine myocarditis were younger than those with post–COVID-19 and conventional myocarditis (mean [SD] age of 25.9 [8.6], 31.0 [10.9], and 28.3 [9.4] years, respectively) and were more frequently men (84%, 67%, and 79%). Patients with postvaccine myocarditis had a lower standardized incidence of the composite clinical outcome than those with conventional myocarditis (32/558 vs 497/3779 events; weighted hazard ratio, 0.55 [95% CI, 0.36-0.86]), whereas individuals with post–COVID-19 myocarditis had similar results (36/298 events; weighted hazard ratio, 1.04 [95% CI, 0.70-1.52]).

And

> Patients with post–COVID-19 mRNA vaccination myocarditis, contrary to those with post–COVID-19 myocarditis, show a lower frequency of cardiovascular complications than those with conventional myocarditis at 18 months.

Why would you not focus on the higher incidences of myocarditis after vaccines, is a good, but different question.

Basically, I'm going to have to look at this during daylight hours to see what the paper actually says as opposed to the reporting of the paper.

(Which essentially means I'll take a look at it Thursday or Friday after going back to Days).

My thoughts are also that since the vaccine group was younger it had implications that the vaccine itself was more likely to hit young and healthy people while covid older and people potentially with cardiovascular issues already existing. It would make it more likely to show in results that post covid people had the worst complications after.

Because it was very specifically young men who were hit, it isn't easy to compare to a random post covid cohort. Even after trying to control for everything I don't think it is feasible.

Ooh nice catch, that didn't jump out to me at first skimming. In addition to this issue you noted, the other more fundamental issue is that their "clinical outcomes" table is not stratified in any fashion.

So the results are meaningless, we know from previous studies that young makes are more likely to get vax myocarditis than covid myocarditis, so all this study effectively tells us is that younger people are better at healing than older people.

Fwiw Vinay Prasad's analysis of this paper: https://www.drvinayprasad.com/p/a-new-jama-paper-shows-it-is...

Remember there is still survival bias here. We’re not seeing the complications from people who died of the infection.

Yet another study with a deliberately misleading headline that ignores stratification. Look at Table 2 and the actual results are clear as day, 18-24 has 44% post-vax and 19% post-covid and males have 84% post-vax and 67% post-covid. Two-variable stratification would probably give even more severe discrepancies.

The "clinical outcomes" table isn't stratified by age or sex so you can't meaningfully conclude anything.

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