A bus driver wearing a mask pulls away from a stop in Portland on Wednesday Feb. 10, 2021. Credit: Troy R. Bennett / BDN

Maine health officials announced Wednesday that a new coronavirus strain that originated in the United Kingdom was detected here. The variant has worried scientists, as early data suggest it is both more contagious and more deadly than the version circulating in the U.S. for a year.

The person who tested positive for the new strain, a Franklin County resident, had a history of international travel, according to the Maine Center for Disease Control and Prevention, so the case does not mean that the new strain is widely circulating in Maine right now.

But Nirav Shah, director of the Maine Center for Disease Control and Prevention, identified the strain as one of the main causes for concern as Maine’s virus trajectory as cases, hospitalizations and virus deaths continue to decline. Here is what you need to know.

Where did the new variant come from?

The new coronavirus variant detected in Maine this week originated in the U.K. All viruses mutate, meaning their genetic code undergoes small, random changes as they copy themselves. Most mutations have no impact on the spread of the disease.

But this mutation of the virus led to a strain more contagious than previous versions. That strain quickly became the predominant one in the U.K., and has been detected in three dozen U.S. states with Maine now among them.

How much more contagious is it?

Various estimates suggest the U.K. strain may be anywhere between 20 and 70 percent more transmissible than previous versions circulating in the U.S.

The average number of people that each person with the virus infects is known as the basic reproduction number. When that number is below one, cases decline. When it is greater than one, cases increase. In Maine, cases have been decreasing for several weeks, suggesting that the reproduction number of the virus is currently below one.

If the new strain starts to spread widely in Maine, it could push the reproduction number back above one, and cases would rise again. That is the scenario health officials worry about. But other measures, such as physical distancing and use of face coverings, can also bring the reproduction number back down and stop the virus from spreading.

Does the variant lead to more severe illness?

Health officials initially thought the U.K. variant was not more severe than other versions of the virus, but the consensus has shifted over the past month. A paper from British researchers in late January concluded there was “a realistic possibility” that the new variant was more deadly, though they acknowledged data was limited and said they expect more definitive results in the coming months.

Shah said Thursday that the Mainer who tested positive for the new variant was “doing well,” but that some members of that person’s family had also tested positive for the virus.

How is Maine testing for new variants?

Maine has been testing for the U.K. strain, and other variants, by sending a fraction of positive virus samples to scientists and the U.S. Centers for Disease Control as well as the Bar Harbor-based Jackson Laboratory. Those labs perform genetic testing, which is much more intensive than the basic tests used to determine whether someone has the coronavirus.

Maine is among the states able to test the most for new strains, Shah said. But he said the Maine CDC is planning to increase its capacity by working with those partners as well as beginning testing at its own lab in Augusta.

What other variants of the virus are out there?

There are many variants of the virus, but most are not concerning. In addition to the U.K. variant, scientists are worried about an especially contagious strain that originated in South Africa and has been identified in a handful of U.S. states. Shah said it is “likely” that Maine will detect other variants, as well as more cases of the U.K. variant.

Do vaccines protect against new variants?

Both the Pfizer and Moderna vaccines are effective against the U.K. variant, scientists say. Those vaccines, the only two currently being administered in Maine, seem to be effective against other variants too, although clinical trials have been limited.

I’m not eligible to be vaccinated. What else can I do to protect myself?

Physical distancing and using face coverings continue to help protect against the virus, including the new strain. A face covering is more effective if it fits tightly to your face, Shah said. One way to do that is by wearing a cotton face covering over a regular surgical mask.

“If we can keep up our guard, keep up our masks and keep vaccinating, my hope is we can outrun the variants and be back squarely on that return to normalcy as quickly as possible,” Shah said.