On a recent morning, Neil Meehan opened a spreadsheet he has come to dread.

It showed the number of intensive-care beds available in an area of New Hampshire that is home to 350,000 people: two.

A day earlier, there was just one. Very often there are none.

Meehan, the chief physician executive at Exeter Hospital, has worked in emergency medicine for nearly three decades. He has lost track of the number of unprecedented things he has witnessed during this second pandemic winter as virus cases and hospitalizations in the state hit record highs.

His hospital has canceled elective surgeries and placed adult patients in pediatric wards. There are members of the National Guard carrying out support tasks. One seriously ill patient had to wait a week for a transfer to a larger hospital that could treat his condition, a move that normally would have taken hours.

“You have duress in the system that I have never seen before,” said Meehan, 56.

Across New England and the northeastern United States, hospitals are struggling with an overwhelming burden of patients amid a COVID-19 surge that has struck harder and faster than experts expected, even in some of the most highly vaccinated states in the country.

The infections – nearly all driven by the delta variant, not its new cousin omicron – have led to record COVID hospitalizations in Vermont, New Hampshire and Maine. All three states have experienced their biggest surges in cases since the pandemic began and asked for federal help, another first. President Joe Biden announced Tuesday that the government will send emergency medical teams to Vermont and New Hampshire and ambulance crews to Maine.

In Massachusetts, Rhode Island and Connecticut, COVID hospitalizations have soared in recent weeks, although they remain below previous peaks. Yet the winter surge comes at a time when hospitals were already grappling with a staffing shortage combined with an influx of people who had delayed care and an increase in patients battling mental illness. Doctors fear that a large wave of omicron cases could increase the burden even further.

“It’s definitely as bad as it’s ever been,” said Eric Dickson, chief executive of UMass Memorial Health in Worcester. “I can use a New England analogy. Snowstorms, right? You get a bad snowstorm and oh, you deal with it. But you get one on top of that, and now you’ve got all that snow from before that you have to manage. And that’s really what it’s feeling like now – it’s just piling up.”

Interviews with 10 hospital leaders across the region revealed a grave picture. Executives at smaller and midsized hospitals said that it has become exceedingly difficult to secure care at higher-level facilities in the region and they worry that delays in transferring patients could have life-threatening consequences. Several said they were discussing whether they might need to implement standards for rationing care.

In Rhode Island, the president of an association of emergency doctors warned in a letter to the governor last week that the situation had become “acutely untenable” and “any added strain right now will lead to the collapse of the healthcare system.”

The emergence of the omicron variant represents a major unknown. The variant is already present across New England and doctors said they expected it to become the dominant strain shortly. They oscillated between optimism that the variant appears to cause milder illness and pessimism that the sheer number of infections could overwhelm hospitals.

Doctors in the region all said that a substantial majority of the patients currently hospitalized with COVID – between 60% and 80% – were unvaccinated. The breakthrough cases that end up in the hospital tend to be milder and are concentrated among older patients and people with other health conditions, they said.

Most state leaders in New England have been reluctant to reimpose mask mandates, but several have announced plans to distribute millions of free tests. On Tuesday, Massachusetts Gov. Charlie Baker, R, said he was activating up to 500 members of the National Guard to assist stretched hospitals.

The recent experience of states in New England is especially dispiriting given their vaccination rates. In Vermont, long lauded for its handling of the pandemic, 77% of the population is fully vaccinated, compared with nearly 62% nationwide. In Maine, the same figure is 75%. In Massachusetts, it’s 74%.

This fall, as colder weather pushed people indoors and children returned to school, transmission began to accelerate. In places such as Vermont, New Hampshire and Maine, which were relatively unscathed by previous surges, there was also a lower level of prior exposure to the virus. Meanwhile, vaccine-induced immunity was waning in those who had flocked to get their shots early in 2021.

Matthew Fox, an epidemiologist at Boston University, emphasized that vaccines are “still very effective” at preventing serious illness and death. But when it comes to vaccines preventing infections, “we thought it would be a greater benefit than we’re observing.”

Fox said that difference could be due to waning immunity, or to the delta variant itself, which emerged after vaccines were developed. “If you put it all together, it’s just more transmission than we would have liked,” he said. The highly contagious omicron variant, meanwhile, can spread among people who are fully vaccinated and boosted.

The high vaccination rates in places such as Vermont and Maine masked considerable variations at the county level, experts said. “People say, ‘Oh, Maine’s doing really well,’ but when you peel the onion layers, what you see is two states,” said Dora Anne Mills, chief health improvement officer at MaineHealth. While 83% of the population in Cumberland County – home to the city of Portland – is fully vaccinated, that same figure slides to below or near 60% in several predominantly rural counties.

Mills said her group of hospitals had scrambled to find more space – canceling elective surgeries, treating patients in recovery rooms for the first time – but she was anxious about the coming weeks because “we could very well be finding out what the limit of that capacity is.”

Nirav Shah, director of the Maine Center for Disease Control and Prevention, echoed that sentiment. “It is not out of the realm of possibility that we will approach a time where ICU beds will not be available,” Shah recently told the Portland Press Herald. “Not just for COVID patients but for any patient.” He said the state is making plans to avoid that situation, which he likened to a “big pileup on the highway.”

In neighboring New Hampshire, where vaccination rates are lower, hospitals have been flooded with COVID patients. Jocelyn Caple is chief medical officer of Valley Regional Hospital, a 21-bed facility in Claremont. She said that 50% or more of her beds on any given day are now taken up by patients with COVID. Her greatest concern is finding spots for critically ill patients of all kinds at higher-level hospitals. “The sense that the entire system is frozen with an inability to transfer patients around is the most worrisome aspect,” Caple said.

In New Hampshire, Maine and Vermont, COVID hospitalizations have touched their highest point in the pandemic in December. For New Hampshire, they peaked at 478 according to state figures. In Vermont, they hit 94. That figure may not sound large to other parts of the country, said Trey Dobson, chief medical officer at Southwestern Vermont Medical Center. But in a low-population state like Vermont – home to just 600,000 people in total – it is considerable, he said.

“What we have going right now is what I would call a triple whammy,” Dobson said. There is an influx of patients coming into hospitals, both with COVID and other ailments; hospitals are having difficulty discharging patients to rehabilitation facilities and nursing homes, which are also strapped for staff; and hospitals can’t find beds for patients at larger, more specialized facilities.

Dobson said his hospital has called as far away as Philadelphia to find appropriate beds, and there have been days “where we’ve made 20 calls and not found someone who could take a patient.”

In Massachusetts, the number of patients hospitalized with COVID has swelled over the past month, to more than 1,600 as of Monday, compared with 700 a month earlier. Hospitals are struggling to cope with the added burden. Ron Walls, chief operating officer of Mass General Brigham, the state’s largest hospital system, said that starting in the late summer, hospitals saw patients returning “in absolutely unprecedented numbers” as the pandemic appeared to recede. The surge in COVID cases is “stressing an already stressed system,” Walls said.

Mark Keroack, the chief executive of Baystate Health, the main hospital system in the western part of Massachusetts, said his facilities are licensed to treat 998 patients at a time. During the past month, however, the number of patients admitted jumped to as high as 1,200. The hospitals are now 10 percentage points over capacity on a regular basis – something he has never seen before.

Baystate is the only health-care provider in its part of the state that offers the highest level of trauma services. “By God, if we get jammed up to the point where we can’t take any more, it’s serious,” said Keroack. “Where can people go? All the big systems in Massachusetts are fighting the same battle we are.” Keroack said that one patient elsewhere in the state who required an advanced life support treatment – pumping and oxygenating a patient’s blood outside the body – had been transferred from Massachusetts to Virginia this month.

Meanwhile, Keroack’s hospital has begun reviewing its policies on how to ration medical care in an ethical way, also known as crisis standards of care, should that become necessary. “I’m sitting here, staring at the barrel of this gun,” he said, referring to the rationing policy. He worries that his hospital might “actually be putting it into use before January is out.”

Under such standards, doctors make decisions about how to prioritize resources, including whether to treat someone based on age and severity of illness. No one wants to take that step, said Dickson, the hospital executive in Worcester. But “effectively that’s what happens when you run out of space,” he said.

His hospital has stopped taking patient transfers except for the most serious trauma cases – people suffering from strokes, heart attacks and brain hemorrhages – and it’s become “really hard even to take those,” said Dickson. That leaves smaller community hospitals trying to care for patients with other potentially life-threatening surgical emergencies, he said.

Doctors say they feel like they’re shouting into a void, delivering news that a pandemic-weary population no longer wants to hear. “You come into work and say, ‘This is the worst it’s ever been,’ ” said Dickson. “And then you come in the next day and it’s even worse.”