Side effects can be uncommon while also passing our prior extremely low thresholds for acceptable vaccine safety. That might change the recommendation about who should get it or how often.

Cardiovascular deaths have increased since Covid. Makes sense, because Covid causes heart damage. The vaccine also produces the thing that causes the heart damage - the spike protein - so there's at least a mechanism at play for the vaccine to cause similar looking damage.

And while mRNA vaccines have been tested for decades, the Covid vaccine was only "tested" during the pandemic because we created it on the spot. At this point over 70% of the US population has had both Covid and the vaccine. So if someone drops dead from viral heart disease, there's no way to know if it was from one or the other. We don't have pre-pandemic trials of this vaccine to compare to.

> You say “anything is possible” like having heart failure due to other causes is some absurdly rare thing.

Viral heart damage is rare.

Additionally, in my personal case, the symptoms of heart damage were present for nearly two months before a diagnosis. Early concerns about the vaccine were dismissed by pointing out that side effects from vaccines present very soon - hours, days - after administering. But it's entirely possible to get viral heart damage, not notice it, and chug along for quite a while before it kills you, if it ever does.

All I'm saying is that there seems to be a clear mechanism for the vaccine to cause heart damage, and that I'm not convinced that we can even really know the true rate of damage caused by the vaccine because most people have both been infected with Covid and received the vaccine.

I'm not making any claims about the magnitude, but I don't think it's anything crazy like I dunno, that half of everyone gets heart damage from the shot. But I wouldn't be surprised if it's just high enough that it changes the calculus for people who aren't in a high risk group.

I want to be clear that I think mRNA vaccines are revolutionary and a good thing.

But it also seems like there's more room for catastrophic error because you're no longer just injecting a static dose of dead material. I'm sure we'll also see multiple versions of future vaccines tailored to genetic variations in the population, things like that. For example, maybe some people produce way more spike protein than others from the shot? Maybe that's a small group so it doesn't present in routine testing?

It just seems like we're in the early stages of being able to administer these things as safely as we're used to. Maybe we got lucky with this one. Who knows.

(Some of my questions might have answers and I'm just not aware of them.)