The US will require UK travelers to have a negative coronavirus test

People traveling immediately after the holiday may face uncertainties: many private clinics and test labs are closed on Christmas Day, so testing within the 72 hour window can be difficult, especially for PCR screening, which should be sent to a laboratory and can take several days to process.

The rapid antigen test, a relatively new tool for detecting the virus, gives a result in about 30 minutes, but is not so widely available, although it is cheaper. Heathrow airport, for example, charges passengers about $ 130 for PCR results in 48 hours and about $ 60 for antigen tests with results in 45 minutes.

Both tests are offered at major British airports – including Heathrow and Gatwick, London’s two main distribution centers and Manchester Airport – but passengers must register in advance. It was not clear how many would be able to take a test and get the result in time to travel.

The introduction of new travel restrictions raised concerns that travelers to the United States would flock to the airport, as Londoners did at train stations last Saturday, when stricter domestic rules were announced. But Heathrow officials on Friday described a normal, though quieter, flow of passengers typical of Christmas Day, with most seeming to travel on long-haul flights.

Several airlines have previously announced policies requiring proof of a negative test following a demand from New York Governor Andrew M. Cuomo that passengers arriving from London to John F. Kennedy International Airport would need to provide documentation of a negative flight result. test.

“We cannot allow history to repeat itself with this new variant”, Mr. Cuomo had written on Twitter.

Also on Thursday, Governor Phil Murphy of New Jersey said that passengers arriving at Newark airport need negative exams 72 hours before departure to enter.

American travel requirements are less draconian than those in other countries in Europe and Asia, which prevented all travelers from Britain after the emergence of the new coronavirus variant. Experts doubt that travel bans could prevent the spread of the variant. In fact, Dr. Anthony S. Fauci, the United States’ leading infectious disease specialist, said there was a good chance that the variant was already in the country.