Maine’s COVID-19 case numbers have stabilized without any significant change for nearly three weeks, ending a steep drop in cases from the January peak of the omicron surge.

Since March 12, the seven-day average of daily new cases has hovered around 200 and on Friday stood at 197. While that’s down from about an average of 850 cases a day on March 1, the decline in case counts has since stalled.

The more contagious omicron BA.2 subvariant is likely the cause of the plateau, said Dr. Dora Anne Mills, chief health improvement officer for MaineHealth, the parent organization of Maine Medical Center and seven other Maine hospitals.

The BA.2 omicron subvariant is now the dominant variant in the United States, accounting for more than half of the samples tested. In Maine, the latest Maine Center for Disease Control and Prevention report shows 10.4 percent of positive tests sampled in March were BA.2, although there are other indications that levels are much higher. Screening of positive tests conducted at Walgreens show about 37 percent of the samples in Maine are currently the BA.2 subvariant, the pharmacy chain said.

“We don’t know what the next two to three weeks are going to bring. Are we going to see an uptick, a plateau, a surge? We don’t know,” Mills said. “We’ll know what happened after it happened.”

Mills said Europe’s experience with the omicron subvariant is so varied that it’s difficult to draw any conclusions. The subvariant has been blamed for case surges in some countries in Europe. But it hit at varying times, spreading in some countries before the omicron surge peaked.

“On the good news side, because we had such a tragic, strong surge of omicron this winter, our background immunity from vaccination and infection is high, so there’s a possibility we wouldn’t see a big surge,” Mills said.

She said even if there’s a jump in cases, hospitalization increases may not follow because of high immunity levels and increasing access to treatments, such as Paxlovid anti-viral pills.

“It’s a much different scenario than even a year ago,” Mills said. “We are in a much better place.”

Maine has one of the highest vaccination rates in the country, with 74 percent of the state’s residents fully vaccinated, and 44 percent boosted.

Maine reported 206 new cases of COVID-19 on Thursday and one additional death. Since the pandemic began, Maine has recorded 235,790 cases of COVID-19 and 2,202 deaths.

The number of hospitalized COVID patients in Maine stood at 97 on Wednesday, with 16 in critical care and four on ventilators. The hospitalization number has hovered just below 100 patients for 11 days after plummeting 78 percent from a peak of 436 on Jan. 13.

Meanwhile, more people are now eligible for boosters, as federal regulators this week approved a second booster for anyone 50 and older. People who received the one-shot Johnson & Johnson vaccine and have gotten their first booster are now eligible for a second booster.

Dr. Nirav Shah, Maine CDC director, said in a tweet Wednesday that “if you are eligible for a second booster, you should get one. They are available, free of charge to you and resoundingly safe. Data from one large population study showed a significant mortality benefit among those who received a second booster versus one.”

The Maine CDC has compiled a list of vaccination providers on its website.