Health officials say the spread of a more contagious version of the pandemic coronavirus underscores the importance of people avoiding spring break leisure travel.

Warnings on travel aren't new, nor have they been updated specifically because of the growing number of variant cases in Minnesota and other states.

But recent variant infections in the state, including clusters linked last week to youth athletics in Carver County, highlight the risk with getaways, even as more people get vaccinated, health officials say.

"We know spring break is approaching for many schools and this is often a time for people to head out on leisure travel," said Dr. Ruth Lynfield, state epidemiologist. "We remain concerned about travel during a pandemic and we urge Minnesotans to consider delaying nonessential travel."

Unnecessary travel is "highly discouraged," state health officials say, and those who must do so should follow safety guidance from the U.S. Centers for Disease Control and Prevention (CDC). That includes getting tested two to three days before leaving, Lynfield said, and limiting or avoiding contact with others for two weeks before the trip.

Overall, Minnesota has found 165 cases of a variant called B.1.1.7, which was first identified in the United Kingdom last year. The variant is a more transmissible and likely more virulent form of the pandemic virus. Health officials say that among those infected in Minnesota, eight have been hospitalized and one person has died.

As of Thursday, 2,672 cases of B.1.1.7 had been reported across 48 states, although the tally is believed to be a significant undercount.

"Delay nonessential travel if that is possible," Lynfield said Friday during a news conference to discuss the Carver County clusters.

On Sunday, the state Health Department reported 897 more coronavirus infections and four deaths linked to COVID-19. With the latest numbers, the seven-day average for new cases stood at about 774.

Since mid-February, the average for new cases in Minnesota has been hovering between 750 and 800 infections per day — well below the peak of just over 7,000 cases per day in November.

Growing quickly

The spread of more contagious versions of SARS-CoV-2 has raised concerns among health officials that the pandemic could accelerate once again.

In addition to B.1.1.7, the state Health Department is watching for two other variants of concern but has found only two cases of one first identified in Brazil and no cases of one seen in South Africa.

Those two variants are less common throughout the U.S., and scientists are thankful since the strains seem to have some ability to escape protection developed by vaccines or previous infections.

To track the spread of all three, health officials are performing genetic sequencing on 150 to 200 virus samples each week. Cases of B.1.1.7 have grown quickly since the first five cases were reported Jan. 9, although health officials say they can't precisely describe the rate of spread in Minnesota.

Whereas some estimate cases are doubling every 10 days in other states, Minnesota isn't doing enough sequencing of randomly selected specimens to estimate a doubling time, said Sara Vetter, interim director of the state public health lab.

"We are targeting areas where we're afraid there might be variants ... so our numbers are kind of skewed," she said last week.

A paper published in February by Minnesota health officials showing that some of the first B.1.1.7 cases in the state involved out-of-state travelers caught the attention of Dr. Rochelle Walensky, director of the CDC.

"Don't travel," Walensky said during a February interview with the editor at the Journal of the American Medical Association. "We really, really would advocate for not traveling right now."

Infections caused by the B.1.1.7 variant have surfaced in all seven Twin Cities metro-area counties. It also has been detected in Blue Earth, Chisago, Isanti, Kanabec, Meeker, Mille Lacs, Pine and Wright counties.

The state has identified several clusters of B.1.1.7 cases, Lynfield said, and has spotted spread within households. The good news, she said, is that people can stop the spread of the variant — just like the more common form of the virus — by wearing masks, maintaining distance, washing hands and following other standard recommendations.

Those who travel should get tested three to five days after their return, Lynfield said, and self-quarantine for up to 14 days.

"That provides us the security that we need — that if they picked up a variant ... that they are staying home and they are testing so we would be able to identify it," she said.

"Even with the positive momentum we see on vaccines, so many Minnesotans are still vulnerable. And we could see another spike in cases around the state if we are not careful for the next few months."

Christopher Snowbeck • 612-673-4744