Travellers from Europe to the United States are from December 6th required to provide a negative Covid test before boarding the plane, under new rules announced by the White House last week.

The White House said that all travellers to the US – vaccinated or not – would need to provide a negative Covid test carried out within one day of departure. The rules took effect at 5:01am GMT (or 6:01am in Denmark) on Monday and apply to all non-citizens and non-US residents.

Previously, vaccinated travellers from Europe could present a negative test result obtained within three days of their time of departure. For unvaccinated travellers the requirement was a negative test within one day.

The new one-day testing requirement would apply equally to US citizens as well as foreign nationals arriving in the US. It applies to any traveller over the age of 2.

The pre-travel period for which a test is valid has been set as 1 day rather than 24 hours.

According to the CDC: “For example, if your flight is at 1pm on a Friday, you could board with a negative test that was taken any time on the prior Thursday.”

The US has accepted both the antigenic and PCR tests for the purpose of travel.

The US, which reported its first case of the Omicron variant on Wednesday last week, said on Monday cases have now been found in 16 states. But it has stopped short of imposing mandatory quarantine on arrivals.

“Our doctors believe tightening testing requirements for pre-departure will help catch more cases, potential cases of people who may be positive and inside the country,” a senior administration official last week told CNBC. “And so now is the right time to do it. And we can implement it very quickly.”