Minnesota reported Saturday its first cases of a new variant of the pandemic coronavirus, a strain that has stoked worldwide concern for apparently spreading more quickly than others.

First detected last year in the United Kingdom, the variant was identified in specimens from five residents of four Twin Cities metro area counties, according to an announcement by the Minnesota Department of Health.

The variant strain is not thought to be more virulent than those that have been widely circulating in Minnesota, Kris Ehresmann, the state's director of infectious diseases, said in a statement. But Ehresmann said the prospect of a more contagious variant underscores the importance of slowing the spread by wearing masks, maintaining social distance and quarantining if exposed to a positive case.

"It's important to note that this variant strain of the virus has been found in other states in the U.S., so we were expecting to find the virus in Minnesota. Knowing that it is now here does not change our current public health recommendations," state epidemiologist Ruth Lynfield said in a statement Saturday.

"While it is thought to be more easily spread from one person to another, it has not been found to cause more serious disease," she added. "With RNA viruses, like SARS-CoV-2, the virus that causes COVID-19, it is not unexpected to see new, more successful strains emerge."

The variant strain of SARS-CoV-2 was first detected in the United Kingdom in September and has been found around the world. The Centers for Disease Control and Prevention (CDC) says 63 cases of the variant strain have been found in eight states as of Jan. 8.

Its arrival in Minnesota is not surprising, but it is troubling since it raises the potential for more spread, said Michael Osterholm of the Center for Infectious Disease Research and Policy at the University of Minnesota.

"It should be a red alert to localities that this variant is now here, and we have to be even more concerned about its potential to cause more infections and what that will do to our health care system," Osterholm said. "This will just add to the capacity challenges we've already had."

One report released last week suggested the variant is 37% more infectious than more common strains, said Dr. David Boulware, an infectious disease specialist at the University of Minnesota. The absolute difference in rates was just 4.2 percentage points — among those infected with the variant, 15.6% of contacts tested positive, Boulware said, whereas people infected with more common strains passed it to 11.4% of contacts.

"The best way to prevent exposure to the B117 variant is to minimize close contact to other people not in your household," he wrote in an e-mail.

The five Minnesotans with the variant range in age from 15 to 37, according to the Health Department, and the onset of their illness ranged from Dec. 16 to Dec. 31. Health officials believe none of those infected with the strain has been hospitalized.

Two of the cases reported international travel, the Health Department said, and one did not. Travel histories weren't yet known for the others. Health officials say they are re-interviewing those who tested positive for the variant strain to better understand how they might have been exposed to it and learn more about their close contacts.

Preliminary studies have suggested that new vaccines against COVID-19 are effective against the variant strain, Ehresmann said.

"Whether this new strain infects more people will be determined to a large degree by how rigorously we all practice those protective measures that are so important," Lynfield said. "Getting as many people vaccinated as possible will also be critical in the control of the spread of this variant and the emergence of other variants."

Earlier Saturday, health officials reported the statewide tally for vaccines administered jumped significantly by more than 15,000 in the latest data release, for a total 119,744 doses so far. State officials have said reporting delays mean daily figures understate the total for doses administered; the count doesn't include vaccinations at federal facilities that have their own supplies.

Four of the variant strain cases in Minnesota were identified through the state's public health laboratory, and one was identified through the CDC. The results were confirmed on Saturday.

Christopher Snowbeck • 612-673-4744

Twitter: @chrissnowbeck