Mr. Zients cited the pace of vaccinations administered globally as a reason for the administration’s pivot. The decision also comes on the eve of a visit by Prime Minister Boris Johnson, who was expected to press Mr. Biden to lift the ban. British officials had hoped the president would announce a relaxation of restrictions when he came to Cornwall, England, in June for the Group of 7 summit meeting and were disappointed when he did not. Their frustration has only deepened since then.
The easing of the travel restrictions also comes as the administration has sought to reduce tensions with another ally in France after the United States kept Paris in the dark as they secretly negotiated an agreement with Australia to build nuclear submarines.
British officials note that the United States had not imposed a similar ban on people from Caribbean nations, which had a higher rate of infection than Britain, or from Argentina, which had lower percentage of its population vaccinated. About 82 percent of people in Britain above the age of 16 have had two shots.
Britain and several European Union countries allow fully vaccinated people from the United States to travel without quarantining, and officials there were annoyed when the United States did not reciprocate.
The ban, European officials point out, has kept families separated since early 2020, as the coronavirus was erupting across Europe. European countries have weathered a third wave of infections propelled by the Delta variant. But in several countries, including Britain, infection rates have begun to level off and even decline.
After the announcement, Giovanni Vincenti, 42 years old, an Italian professor who lives in Baltimore, thought about his grandparents abroad would finally get to meet his daughter, who was born last May.
“I am trying not to cry because it’s such a beautiful day,” said Mr. Vincenti. On Monday, Mr. Vincenti’s wife, who is a Polish researcher on vaccines, was already on her computer trying to book a flight for her mother.
Stephen Castle contributed reporting from London.