A man wearing a mask walks by a drugstore on Congress Street in Portland on Wednesday Feb. 24, 2021. Credit: Troy R. Bennett / BDN

Coronavirus case levels have remained stubbornly high in Maine and New England after a sustained decline throughout the U.S. since mid-January.

Maine, which has weathered the pandemic better than virtually all other states, still has better case numbers than all of its immediate neighbors. But the seven-day average of new cases here has still increased nearly 50 percent over the past month. Cases are up even more across New England, a region that has seen lower overall rates since the virus hit a year ago.

Health officials say it is too early to say what accounts for the rise or whether it will continue. Complacency during the vaccine rollout or the spread of more contagious variants are possibilities. Maine and other New England states also continue to maintain higher testing levels than most of the rest of the U.S., which suggests they may be detecting more cases as well.

“With the more widespread availability of the vaccine, people may not necessarily be as careful as they had been in terms of the masking, physical distancing and other behaviors that tend to reduce transmission,” said R. Gibson Parrish, a physician and epidemiologist based in southern Maine who used to work for the U.S. Centers for Disease Control and Prevention.

The increase comes as Maine has done relatively well with its vaccine rollout, with 16 percent of people getting their final dose as of Friday, which is second-highest in New England and one of the top rates in the U.S., according to NPR. Vaccinations have been largely restricted to older Mainers, health care workers, teachers and residents of long-term care facilities.

Partially because of that, Maine’s recent spike is predominantly concentrated in younger people. Nirav Shah, director of the Maine Center of Disease Control and Prevention, said last week that there was some concern about “mask-wearing fatigue.”

While a handful of states — such as Texas and Mississippi — have ditched mask mandates as the vaccine rollout has accelerated, Maine and its New England neighbors have kept them in place. Most states, including Maine, have eased indoor capacity restrictions. A few have allowed bars to reopen for indoor service, a step Maine will take this week.

Parrish noted that new, more contagious variants of the virus could also be contributing to increased transmission. Maine has detected variants from the United Kingdom and South Africa. But he noted that Maine’s ranking relative to other states had more to do with those states improving after a difficult winter than Maine and other New England states backsliding.

When the virus peaked in mid-January, the seven-day average of daily cases nationally rose to about 76 cases per 100,000 people, according to U.S. CDC data. The New England state with the highest current case rate, Rhode Island, sits at less than half that. Maine’s daily rate — though up slightly from last week — is just 14 cases per 100,000 people.

New England states are also testing more than most of the U.S., according to data compiled by Johns Hopkins University. Rhode Island leads the country with 1,562 daily tests per 100,000 people over the past week. Vermont and Massachusetts rank second and third, respectively, in testing, while Maine ranks fifth with 1,105 tests per 100,000 people.

Shah said it was “too early to tell” whether Maine’s uptick is a blip on a return to normal or the start of a concerning trend. But he advised Mainers to continue to take precautions including physical distancing and mask wearing and to get the vaccine when they become eligible.

“Hope is not one of our actionable strategies in public health,” he said.