Colorado and California Report First U.S. Cases of Highly Contagious Covid-19 Variant

First discovered in England, the variant appears to be more transmissible but does not cause a more severe case of the disease

COVID drive-thru test in Colorado
A COVID testing site at Echo Park Stadium on December 30, 2020 in Parker, Colorado. This site is nearby Ebert County, where the first case of a COVID-19 variant that is thought to be more contagious was detected in the United States. Michael Ciaglo / Getty Images

On Tuesday, Colorado reported the first U.S. case of the new, potentially more contagious coronavirus variant first discovered in England, report Carl Zimmer and Bryan Pietsch for the New York Times. A day later, California governor Gavin Newsom reported the variant was found in his state, Vanessa Romo reports for NPR.

Officials say the Colorado patient, a man in his 20s, is being treated in isolation at a medical facility in Elbert County outside Denver, reports Patty Nieberg for the Associated Press (AP). The officials did not comment on the man's condition.

“There is a lot we don’t know about this new Covid-19 variant, but scientists in the United Kingdom are warning the world that it is significantly more contagious,” says Colorado Gov. Jared Polis in a statement. “The health and safety of Coloradans is our top priority, and we will closely monitor this case, as well as all Covid-19 indicators, very closely.”

Health officials in the U.K. announced on December 14 that the new variant of the coronavirus, called B.1.1.7, could be behind an accelerating spread of the disease in parts of England, reported BBC News. A preliminary U.K. report indicates that theB1.1.7 variant may be up to 70 percent more transmissible than the non-variant version of the virus.

Puzzlingly, the Colorado patient has no recent travel history, and the Times notes this raises troubling questions about whether the new variant has already started circulating in parts of the U.S. The California patient, a man in his 30s according to San Diego County officials, also did not travel outside the country, according the the New York Times.

Experts are monitoring the situation closely but emphasize that it is not cause for panic. There is no evidence that the B.1.1.7 variant causes a more severe case of Covid-19, reports Erin Garcia de Jesus for Science News. And nothing currently suggests the approved vaccines will be less effective against the new variant, Stephen Goldstein, an evolutionary virologist at the University of Utah, tells Science News.

To ensure their inoculations guard against the U.K. variant, both Pfizer and Moderna are conducting tests and early results have been promising, report Steve Almasy and Eliott C. McLaughlin for CNN.

"We're starting to see some data that some of the monoclonal antibodies we have continue to work against this new strain. So I do expect that the vaccines will continue to be effective," Ashish Jha, the Dean of the Brown University School of Public Health, tells CNN. "And if on the outside chance that [they aren't] ... we can make changes to the vaccine. But I don't think that's going to be necessary. Certainly not in the short to medium run."

William Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health tells the Times that though the appearance of B.1.1.7 in Colorado “should not be cause for panic… It is cause to redouble our efforts at preventing the virus from getting the opportunity to spread.”

In response to the new variant, dozens of countries around the world have banned travel from the U.K. Late last week, the U.S. Centers for Disease Control and Prevention (CDC) announced a new rule that all travelers—even those with American passports—would be required to show proof of a negative coronavirus test when they arrived in the country.

It’s not unusual for a virus to undergo mutations as it reproduces within a population, according the AP. But if the new variant does turn out to be significantly more transmissible, it could place additional pressure on already strained U.S. hospitals at a time when air travel within the country recently reached its highest peak since the pandemic began.

“Now I’m worried there will be another spring wave due to the variant,” Trevor Bedford, a researcher at the Fred Hutchinson Cancer Research Center in Seattle, tells the AP. “It’s a race with the vaccine, but now the virus has just gotten a little bit faster.”