The U.S.A. shut down travel from 7 countries. Not sure if that is best, but I am fine with it, for now. No doubt there will be spread worldwide from S. Africa regardless of this shutdown. This shutdown should buy the U.S.A. a few weeks to slow things down and figure out how bad it will become, how good our vaccines are against this variant, and adjust protocols amongst those willing to adjust. Too many of our fellow Americans are willing to endanger friends, relatives, and neighbors by not vaccinating or following protocols.
We are big-brained mammals capable of acting collectively in our interest. We have outliers incapable of acting in our collective interest.