William,

I have to disagree in part. A large part of medicine is built on "most likely." Saying a therapy is "most likely safe" means we can move forward with a therapy with reasonable certainty that it is safe. Of course, this is not foolproof and there have been some unfortunate cases when treatments turned out to be dangerous, but phase 3 clinical trials of this nature do a good job of predicting safety of a vaccine. I agree, safety of these vaccines needs to be closely monitored, but I feel this data is sufficient to move forward with emergency authorization. Thanks for your comment!

J