A nationwide shortage of a key treatment that keeps high-risk COVID-19 patients from getting severely ill has left Maine health care providers with a fraction of the supply they need as the omicron variant has driven hospitalizations to their highest levels of the pandemic.

The state’s federal ration of the key treatment this week – 144 doses – is less than a third of what Maine’s doctors prescribed last week and is not expected to grow for several weeks to come, state authorities told hospitals Friday.

The Maine Center for Disease Control and Prevention also told health providers Friday evening that the more contagious omicron was now the dominant strain in Maine. It said estimates from lab samples in the state suggest that the variant now accounts for 70 to 90 percent of COVID-19 cases in the state.

In recent months, doctors have been able to prescribe one of three monoclonal antibody treatments to their COVID-19 patients who – because they were elderly, had pre-existing conditions or were unvaccinated – had a high risk of getting severely ill. If given early, the treatments had been shown to reduce the chance of hospitalization by more than 80 percent.

But by Friday the omicron variant – which is able to circumvent two of the three treatments – became the dominant COVID-19 strain in Maine, prompting the Maine CDC  to advise health care providers to henceforth prescribe only the one that is still effective: sotrovimab IV, which is given in one intravenous injection.

That drug is in limited supply across the country, forcing hospitals to ration treatments to those at the very highest risk. Production is ramping up, but it is expected it will be several weeks before the supply crunch is alleviated.

“Eventually we will be in a very good place where we have excellent supplies, but unfortunately not in time for this surge,” said Dr. Dora Anne Mills, a former Maine CDC director and currently the chief health improvement officer at MaineHealth, the state’s largest hospital network. “If somebody tests positive for COVID and is at high risk for hospitalization, providers are in a real bind.”

Mills said last week that MaineHealth had given out 204 doses of sotrovimab. This week, the hospital network’s allocation will be just 54 doses.

In December, the U.S. Food and Drug Administration approved the use of another treatment, an antiviral pill called Paxlovid, that also appears effective at fighting omicron cases. But its supplies also have been severely depleted in Maine and nationally. Mills said the state had received fewer than 300 doses of the Pfizer-made drug last week and was not expecting another shipment for several weeks.

“Supplies of these oral antiviral therapies are expected to increase over coming weeks, but the extent to which they will increase is unknown,” the Maine CDC told health care professionals in an advisory sent out Friday night.

The Maine CDC also has advised doctors to follow the National Institute of Health’s guidelines for rationing scarce treatments, with patients ranked in four-tiers based on severity of their risk factors.

VACCINATION STILL THE KEY

“We will provide as many patients with treatments as we possibly can and will go as far down the tiers as we can go,” said Matt Marston, vice president of pharmacy at Northern Light Health, the state’s second largest hospital network. “It all depends on how many high-risk patients test positive going forward and how much supply we have.”

Marston said the fallback treatment for many patients is the antiviral remdesivir, which is not in short supply. But that drug is recommended only for people already hospitalized, rather than to prevent people from getting so sick they don’t need to go to the hospital. It’s possible to give it to outpatients, but such an effort is complicated because the drug requires that a patient receive three injections on three consecutive days, which can be difficult for people with work, parenting or transportation challenges.

“The single most effective thing people can do to protect themselves is to get vaccinated,” Marston said. “Prevention is much better than treatment and we need to make sure everybody is taking every opportunity to prevent serious illness.”

Mills agreed. “People need to be extremely careful, because if they have heard that there are readily available medications to keep them from getting severely sick and hospitalized, they can’t count on that now,” she said. “In this respect, we’re back to where we were a year ago.”