First, this is at least 2 weeks to late to have much of an impact.

Worse, though, the UK hasn't banned travel to Schengen states yet. Because there really isn't much point. But the next effect is, the virus could take the UK route to come to the US anyway. If actual containment were the goal, there's no logic that bans the Schengen states and not the UK.

And no, the lack of free movement doesn't matter. Someone from continental Europe with a UK Visa is just as likely to carry the disease as one without.

For the rest, yeah. I really can't think of a worse kind of crisis to hand over to a personality like Trump's.