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Nurse Deanna North, supervisor of ICU nurses at Marshfield Medical Center-Eau Claire, puts on a personal respirator in November before caring for a COVID-19 patient. A new, possibly more contagious strain of COVID-19 has emerged in the United Kingdom and is beginning to pop up in some U.S. states, though Wisconsin hasn't identified any cases of the variant so far.

EAU CLAIRE — A new, potentially more contagious strain of the novel coronavirus that’s been found in Colorado, California and Florida could cause trouble if it makes its way to the Chippewa Valley, and the Eau Claire City-County Health Department is encouraging people to keep wearing masks and avoiding gatherings.

There are no known cases of the new COVID-19 strain in Wisconsin as of Wednesday, but “the state had said it is plausible that it is circulating in (the Wisconsin) region,” said Audrey Boerner, public information officer for the Health Department’s pandemic response, in an email to the Leader-Telegram.

Though there are already multiple variants of COVID-19 circulating, the new variant that’s now running rampant in the U.K. has an “unusually large number of mutations,” the Centers for Disease Control and Prevention said this month.

There’s no evidence that the new strain causes worse symptoms or a higher risk of death, the CDC said, but it “seems to spread more easily and quickly than other variants,” the agency wrote in December.

Currently the Eau Claire City-County Health Department isn’t able to directly monitor for the new COVID-19 strain that’s been popping up in the U.S. — identifying new virus strains can be done via genome sequencing, which the county’s public health lab isn’t equipped for, Boerner said.

Several clinical, research and public health laboratories around Wisconsin are working with the state and CDC to look for the virus strain, she noted.

“Our understanding is that it is only hypothesized to be more transmissible/contagious, but it isn’t known with certainty,” Boerner said.

Most experts say there’s no evidence that the new variant will make the COVID-19 vaccine less effective, according to the CDC.

Variant popping up in U.S.

First identified in September, the variant is now “highly prevalent” in London and southeast England, according to the CDC. It’s also been found in the United States and Canada.

Colorado officials announced Dec. 29 that Colorado National Guardsman in his 20s with no history of travel had contracted the new variant of COVID-19, after being assigned to help out at a nursing home that was in the midst of a virus outbreak.

California found the nation’s second case of the variant the next day; Florida soon followed.

Britain entered a mandatory six-week lockdown this week. Dozens of countries have banned flights from the U.K., and the U.S. started requiring people flying from Britain to get a negative COVID-19 test before their flight.

Though health officials can identify virus strains by genome sequencing, the U.S. is doing relatively little sequencing of COVID-19. As of late December, only about 51,000 of virus samples from the nation’s 17 million cases of COVID-19 had been sequenced, the CDC said.

“Given the small fraction of US infections that have been sequenced, the variant could already be in the United States without having been detected,” the agency wrote in a Dec. 29 update on its website.

If the variant does have a higher rate of transmission, more people could be infected quickly, Boerner said, which could strain hospitals and contact tracers.

“No matter what variant is the most prominent, we want to slow the spread to prevent overwhelming our hospitals,” Boerner said. “Similarly, lower numbers of cases allow for more complete contact tracing.”

She urged the Eau Claire County community to keep wearing face masks, socially distancing, avoiding crowds, ventilating indoor spaces and notifying their close contacts if they test positive.

The Associated Press contributed to this report.

Contact: 715-833-9206,, @sarahaseifert on Twitter

Sarah Seifert is the L-T's education and health reporter. She has worked as a journalist in the Chippewa Valley since 2017 and joined the L-T in 2019. Get in touch at or on Twitter @sarahaseifert.