Earlier quoted context omitted.
But the vaccine causes the body to produce spike protein. The CDC emphasizes the spike protein is harmless, but this new research finds that the spike protein itself can cause damage. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different...
It causes the body to produce it in a limited, fixed quantity in proportion to the number of viable RNA strands that make it into a cell, largely localized at the injection site. Just a guess but this probably means its risk is extremely limited. The wild virus causes this protein to be produced without check. It wouldn't just be the mRNA vaccines, anyway. The viral vector ones, as well as the inactivated virus, and…
The vaccine has to be orders of magnitude safer than the virus, because (essentially) everyone will get the vaccine, but only some will get the disease. E.g. it might be harmful to vaccinate people in New Zealand and Australia at this point, because for now they cannot get the virus.
What these papers (there are 3 independent ones showing very similar results, all coming out in the last month) show is that the vaccine outcome (specific proteins) that were assumed to be inert and only prime the immune system against the virus, are actually active and damaging. That's a big difference -- and the question of whether it makes sense to vaccinate needs to rely on actual science, not "it's a vaccine so must be good and safe" ideology. It also depends on specific attributes (e.g. age, obesity, etc.)
There's an Israeli study showing myocarditis at a rate of 1:20,000 for the 16-30 age bracket, with 1:100,000 overall (all pfizer)[0] ; the US Army stats are 1:250,000 (for a mix of JNJ,Pfizer.Moderna) but I didn't find age distribution - and these are exceptionally lean and fit individuals, compared to the general population.[1]
That's just myocarditis ; it it related to what's described in this paper? I don't know. Are there any other issues? I don't know. And generally speaking, no one else does either. But because everyone gets vaccinated, we require exceptional proofs of safety. Or at least, did before 2020.
[0] https://www.timesofisrael.com/israel-said-probing-link-betwe...
[1] https://www.military.com/daily-news/2021/04/26/pentagon-trac...