A Presidential Proclamation that took effect on 13 March
2020 prohibits foreign nationals from entering the US if they have
been physically present in Europe within 14 days, because of the
risk of transmitting the novel coronavirus.
Background
The Proclamation states that the US Government cannot
effectively evaluate and monitor all of the travellers arriving
from Europe, and that undetected infected individuals could
threaten national security. The travel ban applies to most foreign
nationals who, in the prior 14 days, have been in the Schengen
Area, which comprises Austria, Belgium, Czech Republic, Denmark,
Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy,
Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands,
Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, and
Switzerland. It does not include the United Kingdom, though it
could be expanded later.