A day after the government announced that two cases of the new Omicron coronavirus variant had been discovered in Britain, the health secretary, Sajid Javid, said on Sunday that more were likely to be found, but rejected calls for tougher restrictions on daily life.
On Saturday, the government said that masks would be mandatory on public transportation and in shops in England starting on Tuesday. Tighter testing rules for travelers arriving from abroad would also go into effect that day.
But the government has rejected the idea of ordering people to work from home where possible, introducing vaccine passports in England or requiring masks in restaurants. “This is about taking proportionate action against the risks we face,” Mr. Javid told the BBC on Sunday.
Still, he admitted that the two cases of the variant were unlikely to be the only ones. “There may well be more cases, and that is why when we confirmed these two cases yesterday — one in Essex and one in Nottingham — we immediately went about making sure we had properly traced all their contacts,” he said.
Britain began suspending flights from six southern African nations on Friday, but some travelers had already arrived in London by the time the measure took effect.
Passengers landing in London on Friday were not tested at the airport and were able to leave as usual, including by public transport. Mr. Javid said that all travelers who had arrived from southern Africa within the past 10 days were being contacted and asked to take tests.
“We could not have acted more swiftly,” he said.
By contrast, in Amsterdam, Dutch health officials tested more than 500 passengers who arrived on Friday on two flights from South Africa. Those who were negative were allowed to leave the airport and quarantine at home, or to continue their journeys.
Mr. Javid also urged Britons to quickly get booster shots and said he expected advice “imminently” from scientific experts on expanding the scope of the country’s vaccine program, especially with regard to boosters.
Such measures would, he added, help to “protect the progress we have made so we can continue to look forward to Christmas with family and friends.”