PORTLAND, Maine (AP) — The number of COVID-19 patients in hospital intensive care units reached alarming levels as Maine raced to vaccinate residents — surpassing a threshold of 50% of eligible Mainers being vaccinated on Friday.

More contagious COVID-19 variants are likely playing a role in the growing number of patients in ICU beds, officials said.

Central Maine Medical Center in Lewiston has been experiencing its heaviest COVID-19 inpatient burden in recent weeks. Sixteen of the 21 patients, or more than three-quarters, were in the ICU as of Wednesday, the Portland Press Herald reported.

“It’s a frightening shift. It’s not even subtle,” said Dr. Al Teng, chief of critical care at CMMC’s parent, Central Maine Healthcare. “Patients who were critically ill in previous COVID waves were in their 60s, 70s and 80s, but now we’re seeing them in their 20s. It’s quite a stark progression.”

A similar situation is happening at MaineHealth, the state’s largest hospital network and parent of Maine Medical Center in Portland. During the winter surge, about 3 in 10 of its patients hospitalized with COVID-19 required intensive care, but the proportion is now at least 6 in 10, said Dr. Joan Boomsma, chief medical officer.

There was a similar shift at Northern Light Health, the state’s second largest hospital network, with nearly half of all patients admitted to Eastern Maine Medical Center in Bangor requiring ventilators, said Dr. James Jarvis, the network’s physician incident commander.

The disturbing trend has emerged even as the state races to vaccinate. As of Friday, more than half of Mainers aged 16 and older were fully vaccinated.

“I am proud to report that more than half of Maine people have received their final dose of a vaccine — but there is more work to do to get this pandemic behind us,” Gov. Janet Mills said Friday.

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While some states are returning unused vaccine doses, Maine is not scaling back its vaccination efforts. All told, more than 1.2 million doses have been administered in Maine.

“Maine has placed orders for the maximum number of doses each week since COVID-19 vaccines first became available. We plan to continue doing so,” said Robert Long, spokesperson for the Maine Center for Disease Control and Prevention.

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