Hospitalizations for COVID-19 remained flat at a high level across Maine for a second week running, but the burden has clearly shifted back to hospitals in Portland and Lewiston, giving Bangor’s Eastern Maine Medical Center a respite.

Maine Medical Center in Portland, the state’s largest hospital with 613 beds, has experienced its heaviest week since the pandemic began, with an average of 40.9 COVID-19 inpatients a day for the week ending Thursday. It is the third week in a row that Maine Med has broken its record, which stood at 38 COVID-19 inpatients per day two weeks ago today and 38.4 last week.

Both of Lewiston’s hospitals also had their biggest burdens yet. Central Maine Medical Center cared for an average of 15.4 COVID-19 inpatients each day for the week ending Thursday, up from 11.1 last week, which had also been a record, and 7.7 the week before that. St. Mary’s Regional Medical Center had an average of 7.4 such patients this week, up from 4.9 last week and the previous record of 6.7 set the week before.

Pen Bay Medical Center in Rockport also set a record, averaging 8.3 COVID-19 inpatients per day, up sharply from 1.9 last week and more than double any previous week. MaineHealth, Pen Bay’s parent entity, said it recently designated the hospital as one of the network’s COVID-19 treatment hubs, which accounts for the recent increase.

At the same time, hospitals in Eastern Maine and York County have seen steep reductions in the number of COVID-19 admissions and inpatients after weeks of heavy demand.

EMMC, which was the busiest COVID-19 hospital in the state for much of December, averaged 25.7 COVID-19 inpatients a day for the week ending Thursday, down from 32.1 last week, 47 the week before that and 51.9 the period before that, the highest level of the pandemic.

It’s not clear why the geography of COVID-19 hospitalizations shifted to eastern Maine last month and then back southward, said Dr. James Jarvis, senior vice president at EMMC and physician incident commander for its parent entity, Northern Light Healthcare.

“I was on a conference call this morning with my counterparts at other hospitals across the state, and we couldn’t come up with a good explanation as to why we are seeing this now, or why after Thanksgiving EMMC got hit very hard,” Jarvis said, noting that COVID-19 test positivity rates remain high at Northern Light member hospitals across the state. “There’s really no explanation as to why we are seeing these trends.”

Dr. Dora Anne Mills, a former director of the Maine Center for Disease Control and Prevention who is MaineHealth’s community health improvement officer, concurred.

“We’re just seeing the disease tends to migrate around like that, but that’s not to say that we’re over the hump in northern and Down East Maine,” Mills said. “And the big wild card, which is why I don’t sleep at night, is this new, more contagious variant mutation of the virus that’s been confirmed in Massachusetts and other states and could cause another surge.”

Both of York County’s hospitals saw their inpatient COVID-19 burdens ease considerably after a record-breaking period around New Year’s. SMHC Medical Center, with 158 beds, reported an average of 14.4 such patients a day this week, down sharply from 24 last week and 27 the week before.

Much smaller York Hospital, with 48 beds, finally had substantial relief after an intense month, with an average of 6 COVID-19 inpatients a day, down from 9.3 last week and a record 10.7 the week before.

Wednesday was the worst day yet of the pandemic in terms of the number of people statewide in intensive care for COVID-19 with 71. There were 198 hospitalized overall, not far below the peak level of 207 set Jan. 13.

Mercy Hospital in Portland saw an increase to 11.7 inpatients a day, up from 10 last week and 6.3 the week before, but below its worst week set in early December, when the figure was 14.9 per day.

MaineGeneral in Augusta also saw an increase, to 16.3 inpatients a day, up from 11.3 last week but under its record of 17.4 in the second week of December.

The COVID-19 burden at Mid Coast Hospital in Brunswick increased slightly to 5.1 inpatients per day, up from 4.6 the previous two weeks. The heaviest period for the 198-bed hospital was the week before Christmas, when it hit 9.3.

Two smaller hospitals had their heaviest pandemic burdens yet this week.

Sebasticook Valley Hospital in Pittsfield had 3.7 COVID-19 inpatients a day, up from 1.3 last week and 0.6 the week before. The previous weekly record for the 25-bed hospital was 3.4 set in early December.

A.R. Gould, a 48-bed hospital in Presque Isle, saw a record burden of 5.4 COVID-19 inpatients a day, up from 3.3 last week and 2.6 the week before. The hospital didn’t admit its first COVID-19 inpatient until Oct. 28.

Another Aroostook County hospital, Northern Maine Medical Center in Fort Kent, has declined to share its inpatient numbers with the Press Herald, the only Maine hospital to do so. Federal data for the week ending Jan. 14 indicates the 42-bed hospital had 28 COVID-19 inpatients for the week – or 4 per day, down slightly from 4.3 per day the week before and 1.7 the week before that. The data reported by the U.S. Department of Health and Human Services starting last month lags the Press Herald’s survey by a week.

The federal data for the week ending Jan. 14 also showed Cary Memorial in Caribou, Houlton Regional, and Redington-Fairview General in Skowhegan had COVID-19 inpatients that week.

Many other smaller hospitals had COVID-19 patients for the week ending Thursday, including Franklin Memorial in Farmington, Waldo in Belfast, Inland in Waterville, Lincoln Health in Damariscotta, Maine Coast Hospital in Ellsworth, Mayo Regional in Dover-Foxcroft, and Bridgton and Rumford Hospitals.

Since the start of the pandemic, Maine Med has accumulated the heaviest total COVID-19 hospitalization burden, with more than 4,320 inpatient nights of care. It is followed by EMMC (2,510), SMHC (over 1,880) and MaineGeneral (1,419).

The pandemic continues to rage across the country, with states reporting 184,754 positive tests and 4,367 deaths on Wednesday alone, according to The New York Times tracker, substantially more than either of the two deadliest battles of the Civil War, the Battles of Antietam and Gettysburg, or the 9/11 terrorist attacks, Maine had been one of the best performing states for much of the pandemic, but over the past month it has moved to the middle of the pack, placing 34^th among the states in terms of prevalence of the disease over the seven days ending Wednesday.

Hospitalizations are a lagging indicator in that they typically occur one to three weeks after a person is exposed to the disease, but unlike other metrics, it is not dependent on who and how many people were tested. Hospitalizations can end in three ways: recovery, death, or transfer to another facility.

The Press Herald compiles data directly from the hospitals and networks. The data does not include outpatients or inpatients suspected of having the virus but who were never tested. It includes most of the state’s hospitals, accounting for nearly all of the statewide hospitalizations reported each week by the Maine CDC.