Let’s say a vaccine is safe — you still have to know if it’s actually effective. That’s one of the things measured in these trials. We can’t just say, whoops, a

Let’s say a vaccine is safe — you still have to know if it’s actually effective. That’s one of the things measured in these trials. We can’t just say, whoops, and mail a new dose to everyone. So, the risk isn’t just the safety. It’s about not squandering the precious resources that have been pulled together to manufacture distribute untold numbers of doses of a vaccine.