I had wondered about this as well - in the pool of people who have gotten the J&J vaccine, how many would we expect to have developed a blood clot under normal circumstances anyway?

That's exactly what they'll be studying to see if it's statistically relevant. They're being super cautious. Some would say over cautious but I think it's fine since J&J is currently only 5-10% of the vaccine supply going out. Which means a slight slow down in vaccine supply but not as big a deal as AZ in Europe since that is their main supply.

>A slight slow down is a euphemism for people dying.

We apparently don't know that, which is why they are pausing to examine the safety of the vaccine.

We don't know what? We know that if a slow down causes a delay in people getting vaccines, there will be people dying from COVID.

Not if the vaccine isn't safe.

For the record, I'm not coming down on one side or the other of this argument, just pointing out what the calculus they seem to be operating under is.