First U.S. case of infectious Covid variant reported in Colorado

Evidence suggests the new strain spreads more easily, but that it doesn’t make people sicker and isn’t deadlier. Federal officials say the coronavirus vaccines are expected to protect against the strain.

The variant was likely circulating in the United States for some time. The U.S. sequences far fewer virus samples than other countries, meaning mutations may go unnoticed for longer.

“We need to increase our sequencing,” Adm. Brett Giroir, the nation’s coronavirus testing czar, said Tuesday on MSNBC. “The CDC is doing that both within themselves and a variety of other partners.”

The CDC announced last week that it will require airline passengers traveling from the U.K. to the U.S. to test negative for the coronavirus before flying — and Giroir said “that probably should be extended to other countries.”