In the weeks before President Donald Trump spoke from the Oval Office to announce restrictions on travelers from more than two dozen countries in Europe, thousands of people from the region already had stepped off planes at U.S. airports, and an untold number of them carried the coronavirus.
The same can be said of flights from China in the weeks before the U.S. clamped down on those. Thousands who visited the country where the illness began had entered the United States without any kind of health review.
