VIRUS VARIANT

test. And if someone tests positive for the omicron variant, their close contacts will have to self-isolate for 10 days regardless of their vaccination status. Currently, close contacts are exempt from quarantine rules if they are fully vaccinated.

Johnson also said mask-wearing in shops and on public transportation will be required and that an independent group of scientists that advises the British government on the rollout of coronavirus vaccines has been asked to accelerate the program. This could involve widening the booster program to younger age groups, reducing the time between a second dose and a booster, and allowing older children to get a second dose.

Britain’s Health Department said the two cases in the U.K. were linked and involved travel from southern Africa. One of the two new cases was in the southeastern English town of Brentwood, and the other was in the central city of Nottingham. The two cases are self-isolating with their households.

The government also added four more countries — Angola, Malawi, Mozambique and Zambia — to the country’s travel ban. Six others — Botswana, Eswatini, Lesotho, Namibia, South Africa and Zimbabwe — were added Friday. That means anyone permitted to arrive from those destinations will have to quarantine.

Many countries have slapped restrictions on various southern African countries over the past couple of days — including the U.S., Australia, Brazil, Canada, the European Union, Iran, Japan and Thailand — in response to warnings over the transmissibility of the variant. This is contrary to the advice of the World Health Organization, which has warned against any overreaction before the variant is thoroughly studied.

Despite the banning of flights, there are mounting concerns that the variant has already been widely seeded around the world.

Italy and Germany were the latest to report confirmed cases of the omicron variant.

An Italian who had traveled to Mozambique on business landed in Rome on Nov. 11 and returned to his home near Naples. He and five family members, including two school-age children, have since tested positive, Italian news agency LaPresse said. All are isolating in good condition.

In Germany, the Max von Pettenkofer Institute, a Munichbased microbiology center, said the variant was confirmed in two travelers who arrived on a flight from South Africa on Wednesday. The head of the institute, Oliver Keppler, said genome sequencing has yet to be completed but that it is “proven without doubt that it is this variant,” German news agency dpa reported.

The Dutch public health institute said the variant was “probably found in a number of the tested persons” who were isolated after arriving Friday in Amsterdam on two flights from South Africa. The institute said in a statement that further sequencing analysis is underway to determine for sure that it is the variant. The results were expected today. Sixty-one people were tested.

Israel said it detected the variant in a traveler who had returned from Malawi and was tracing 800 travelers who returned recently from southern African countries.

The variant’s swift spread among young people in South Africa has alarmed health professionals even though there was no immediate indication the variant causes more severe disease.

A number of pharmaceutical companies, including AstraZeneca, Moderna, Novavax and Pfizer, said they have plans in place to adapt their vaccines in light of the emergence of omicron. Pfizer and its partner BioNTech said they expect to be able to tweak their vaccine in around 100 days.

Professor Andrew Pollard, the director of the Oxford Vaccine Group, which developed the AstraZeneca vaccine, expressed cautious optimism that existing vaccines could be effective at preventing serious disease from the variant, noting that most of the mutations appear to be in similar regions as those in other variants.

“At least from a speculative point of view, we have some optimism that the vaccine should still work against a new variant for serious disease, but really we need to wait several weeks to have that confirmed,” Pollard told BBC radio.

Some experts said the variant’s emergence showed how rich nations’ hoarding of vaccines threatens to prolong the pandemic.

Fewer than 6 percent of people in Africa have been fully immunized against COVID-19, and millions of health workers and vulnerable populations have yet to receive a single dose. Those conditions can speed spread of the virus, offering more opportunities for it to evolve into a dangerous variant.

“One of the key factors to emergence of variants may well be low vaccination rates in parts of the world, and the WHO warning that none of us is safe until all of us are safe should be heeded,” said Peter Openshaw, a professor of experimental medicine at Imperial College London.