As of Wednesday, cases of the COVID-19 coronavirus had reached 2,499 in Lincoln County and two new deaths had been reported, taking the county’s death toll to 79.

With more than 213,000 cases and 4,747 deaths statewide reported Wednesday morning by the Mississippi State Department of Health, 167,263 people were nevertheless presumed to have recovered from virus infections — a recovery rate in the state of 78.5%.

Nationwide, the focus midweek was on Colorado, as the first person in the United States known to be infected with a new and apparently more contagious variant of the coronavirus was identified as a Colorado National Guardsman who had been sent to help at a nursing home struggling with an outbreak. Health officials reported a second Guard member may also have been infected.

The cases have triggered a host of questions about how the mutant version circulating in England arrived in the U.S. and whether it is too late to stop it now, with top experts saying it is probably already spreading elsewhere in the country. The discovery has also added urgency to the nation’s vaccination drive.

The two Guard members had been dispatched on Dec. 23 to work at the Good Samaritan Society nursing home in the small town of Simla, in a mostly rural area about 90 miles outside Denver, said Dr. Rachel Herlihy, state epidemiologist. They were among six Guard members sent to the home.

A state laboratory began looking for signs of the variant after its spread was announced in England earlier this month, Herlihy said. Staff and residents at the nursing home who tested positive for the coronavirus are having their samples screened for the variant, and so far no evidence of it has been found, she said.

The confirmed case is in a Colorado man in his 20s who hadn’t been traveling, officials said. He has mild symptoms and is isolating at his home near Denver, while the person with the suspected case is isolating at a Colorado hotel, Herlihy said.

A call to the nursing home was not immediately returned.

The alarming new version was first identified in Britain, where infections are soaring and hospitalizations have climbed to the highest levels on record. It has also been found in several other countries.

Scientists in Britain have found no evidence that it is more lethal or causes more severe illness, and they believe the vaccines now being dispensed will be effective against it.

Nevertheless, the discovery overseas led the U.S. Centers for Disease Control and Prevention to issue rules on Christmas Day requiring travelers arriving from Britain to show proof of a negative COVID-19 test.

The variant is probably still rare in the U.S., but the Colorado patient’s lack of travel history means it is spreading, perhaps seeded by visitors from Britain in November or December, said scientist Trevor Bedford, who studies the spread of COVID-19 at the Fred Hutchinson Cancer Research Center in Seattle.

“Now I’m worried there will be another spring wave due to the variant,” Bedford said. “It’s a race with the vaccine, but now the virus has just gotten a little bit faster.”

“The virus is becoming more fit and we’re like a deer in the headlights,” warned Dr. Eric Topol, head of Scripps Research Translational Institute,

He noted that the U.S. does far less genetic sequencing of virus samples to discover variants than other developed nations, so the finding in Colorado probably means it is already spreading in other parts of the country and it is too late for travel bans.

“We’re behind in finding it. Colorado is likely one of many places it’s landed here,” Topol said. “It’s all over the place. How can you ban travel from everywhere?”

Colorado public health officials are conducting contact tracing to determine its spread, and Gov. Jared Polis said infections are being monitored closely.

British Prime Minister Boris Johnson reported the weekend before Christmas that the variant was moving rapidly through London and southeast England. The region was placed under strict lockdown measures, and dozens of countries banned flights from Britain. France also briefly barred trucks from Britain before allowing them back in, provided the drivers got tested for the virus.

The Associated Press contributed to this report.