It can be difficult to distinguish something that only happens in 1 out of 100,000 cases from the normal background rate until you get enough cases. That’s the purpose of VAERS: to help identify when some rare, unexpected side effect breaks out of background rates. In this case, FDA found ~100 cases out of 12,500,000 vaccinations. In other words, 1 per 125,000.
Anaphylaxis is seen in about 1 in every 400,000 Moderna vaccinations. Blood clots are seen in about 1 in every 470,000 J&J vaccinations. So yes, these are rare. There are a few different side effects. Myocarditis is found in young males too, but what isn’t often noted is that COVID-19 causes it more than a thousand times more frequently in young males. A Big 10 study showed that 2.3% of their college athletes recovering from COVID-19 had myocarditis. That’s 23,000 per million versus somewhere around 11 per million for the mRNA vaccines.
Much ado about very rare and nearly never serious side effects. COVID-19 on the other hand, can have very serious effects. Aside from death, some research has shown that as many as 78% of people infected with COVID-19 have heard damage. That’s not great. So even those who survive can have major issues.
For being so rare, we sure see a lot of it happening.