Additional modeling shows the high portability of the British variant.

A team of British scientists published a worrying study on Wednesday about a newly discovered variant of the coronavirus that has spread to Britain. They warned that the variant was so contagious that new control measures could be needed, such as the closure of schools and universities. Dr. Nicholas Davies, lead author of the study, said the findings were “pretty convincing that faster vaccination would be a really important thing for any country that has to face this or similar variants.”

As of Tuesday, the variant has not been identified in the United States, according to the Centers for Disease Control and Prevention.

The study, published by the Center for Mathematical Modeling of Infectious Diseases at the London School of Hygiene and Tropical Medicine, has not yet been reviewed in a scientific journal. The study compares models as predictors of data on infections, hospitalizations and other variables. Other researchers are studying the variant in laboratory experiments to determine if it is biologically different.

The study found no evidence that the variant was more deadly than the others. But they estimated it to be 56 percent more contagious. On Monday, the British government released an initial estimate of 70 per cent.

Bill Hanage, an epidemiologist with the Harvard TH Chan School of Public Health, who was not involved in the study, said it provided a convincing explanation of the past and potential future of the variant.

This variant, which caught the attention of British researchers this month, is spreading rapidly through London and eastern England. It carries a set of 23 mutations, some of which can make it more contagious.

The authors of the study found more evidence that the variant is indeed spreading faster than the others. For example, they ruled out the possibility that it was becoming more common because outbreaks began in places where people were more likely to come into contact with others.

The researchers built different mathematical models and tested each of them as an explanation for the spread of the variant. They analyzed which spread model best predicts the number of new cases actually confirmed, as well as hospitalization and deaths.

Closing schools by February could buy Britain little time, the researchers found, but lifting additional restrictions would then cause a large return of cases.

Dr. Davies and his colleagues have also considered the protection that vaccines will provide. Vaccine experts are confident that coronavirus vaccines will be able to block the new variant, although this must be confirmed by ongoing laboratory experiments.

Benjamin Mueller contributed to the reporting.