Starting Monday the U.S. will require all air travelers from the United Kingdom to test negative for coronavirus within 72 hours of their departure, the Centers for Disease Control and Prevention has announced.

The big picture:More than 50 countries have restricted air travel to the U.K., as concerns have continued to grow after the nation and the World Health Organization said they'd identified a new variant of COVID-19 within the country.

How it works: Passengers will have to show proof of a negative result on a genetic swab test, known as PCR, or an antigen test that was administered within three days before their flight.

• Airlines will be required to confirm the negative test result of all passengers before they board, and they will have to deny boarding to those who decline to show a test.
• "This additional testing requirement will fortify our protection of the American public to improve their health and safety and ensure responsible international travel," the CDC wrote in a news release late Thursday.

United Airlines, Virgin Atlantic and Delta Air Lines already had a similar policy in place for flights between Britain and the U.S., according to the New York Times.