Colorado officials said the case had been identified by the state’s public health laboratory in a male in his 20s with “no travel history.” The Centers for Disease Control and Prevention has been also been notified of the case, according to the state health officials. “The Centers for Disease Control and Prevention (CDC) is aware of Colorado’s report of the first U.S. cases associated with the U.K. variant of COVID-19,” CDC spokesperson Belsie González said in an email. “In addition to the reported cases in Colorado, we expect that there will be additional cases that are likely to be detected in the coming days,” said González. Public and private labs around the country have ramped up sequencing efforts to search for the U.K. variant, named B.1.1.7. Public health officials in the U.K. have warned it appears to be more transmissible than other strains of COVID-19. “The fact that Colorado has detected this variant first in the nation is a testament to the sophistication of Colorado’s response and the talent of CDPHE’s scientist and lab operations,” said Jill Hunsaker Ryan, executive director of the Colorado Department of Public Health and Environment. Public health laboratories routinely identify variants of the coronavirus in COVID-19 patients, though many mutations to the virus do not affect how it spreads or the symptoms it causes. Colorado health officials said they were conducting contact tracing of the individual case, though they added that the individual was “currently in isolation” and “has no close contacts identified so far.” On Monday, the Trump administration imposed a new requirement for travelers from the U.K. to test negative for COVID-19 before boarding flights to the U.S. U.S. health officials have repeatedly warned that the variant was likely already circulating here, though public health laboratories had yet to identify any cases. Unlike the U.K., the U.S. has sequenced only a small percentage of COVID-19 cases, so variants here are likely to escape detection. As reports about the new U.K. variant emerged earlier this month, the CDC said just 51,000 of the 17 million cases of COVID-19 in the U.S. had been sequenced. Preliminary results published by researchers in the U.K. this week found the COVID-19 variant appeared to be more transmissible but not more deadly. It also seems not to lead to more hospitalizations, nor increase the likelihood of reinfection. Both Pfizer and Moderna have said they believe their COVID-19 vaccines will also offer protection against B.1.1.7, saying that they frequently tested their shots against new virus variants.