(CNN) As coronavirus cases surged across the United States earlier this year, doctors faced a harrowing prospect. Sometime soon, they worried, physicians might have to decide which patients would receive ventilators amid a projected shortage.
It's a crisis Italy faced and one the United States largely avoided. But already, doctors in the US are facing another difficult decision: How to ration limited supplies of an experimental drug shown to be effective against the virus.
"We actually did, ultimately, have enough ventilators," said Dr. Rochelle Walensky, chief of infectious diseases at Massachusetts General Hospital. "But we know the doses of [remdesivir] that we are going to get are not going to be enough to treat every patient that we have in the hospital now and every patient that is going to be coming in for the weeks ahead."
The US Food and Drug Administration authorized remdesivir for emergency use earlier this month in a move to increase access, but the government's distribution of the drug has been opaque and confusing.
There is only enough remdesivir in the world for about 100,000 to 200,000 patients, according to the drug's maker, Gilead Sciences. As the company works to manufacture more, about 40% of its current supply has been reserved for the US, according to the US Department of Health and Human Services.
Last week, the government began distributing vials of remdesivir directly to some hospitals, but it was unclear why some received the drug while others received nothing -- even in hard-hit areas of the country.
After doctors expressed outrage, HHS backtracked on its original plan and decided to give remdesivir to state health departments to manage. But as the drug trickles into hospitals -- mostly in regions with the largest outbreaks -- doctors are grappling with how to ration the few vials they're getting.
And in most states, doctors still haven't received any remdesivir at all, leading to difficult conversations about why patients can't have a drug that White House coronavirus task force member Dr. Anthony Fauci said would set a new "standard of care" for Covid-19.
At Mass General, an impartial committee -- which includes ethicists -- has been putting together guidance on how to allocate the hospital's limited supply, according to Walensky. The group has already begun working through patients' charts, and the hospital has enough remdesivir for about 65 patients.
"This was work that was going on before we received the drug," Walensky said. The committee came together anticipating that "there are going to be patients -- they are currently nameless and faceless -- who are going to need this drug, and we are going to need to figure out how to prioritize it."
Two months ago, medical ethicists floated a similar approach for allocating ventilators. In "The Toughest Triage," published in the New England Journal of Medicine, they suggested insulating doctors on the front lines by leaving decisions to a group "composed of people who have no clinical responsibilities for the care of the patient."
Unlike ventilators, though, remdesivir is not a lifesaving drug -- at least not yet. While it shortened patients' hospital stays by about four days in a clinical trial, it hasn't been shown to reduce the risk of death. Still, it's one of the few tools available with some effect on the virus.
"Perhaps I rest a little easier knowing that we don't know this drug to be the miracle that people are hoping it is," said Walensky. She added that "if this were a cure, if this were a vaccine, I would say it would be even harder."
Even so, "it's nearly an impossible situation to be in medicine when you think that there's something you could and should be doing for somebody, and you don't have it to give."
Officials with Health and Human Services have said it's distributing remdesivir to "areas of the country hardest hit by the pandemic." But the agency has never released the formula it uses to calculate which states get the drug and how much.
California, for example, has seen more than 67,000 coronavirus infections so far -- but hadn't received any remdesivir from the government as of this weekend, according to HHS.
At Zuckerberg San Francisco General Hospital, doctors can only access the drug through restrictive clinical trials or Gilead's "compassionate use" program -- which is only open to children and pregnant women.
"Before I could honestly say to [Covid-19] patients, I've got nothing. But now there is something I could offer but have no ability to do it," said Dr. Annie Luetkemeyer, a professor of infectious diseases at the University of California, San Francisco, who practices at San Francisco General.
"I came home and told my husband that I was so happy the day the press release announced the remdesivir results, and here I am nine days later still admitting patients and not able to prescribe it," she said.
San Francisco General is a public hospital, and while other cities are harder hit -- New York, for example -- San Francisco has sick coronavirus patients too, many of whom come from marginalized communities.
During the H1N1 pandemic, the US Centers for Disease Control and Prevention set up a national system to allocate a different antiviral, peramivir, that had received an emergency use authorization. But no such system exists today, and HHS hasn't released any information beyond a press release issued this weekend, which lists a handful of states receiving remdesivir.
The agency said it "expects" the drug to be delivered to every state and territory, but offered no timeline.
Luetkemeyer, for her part, says she understands the medicine needs to go to the hardest-hit communities. But the haphazard allocation of the drug, with no clear criteria for the regions getting it, is frustrating.
"My God, it's the first thing we've found that has a signal that it's working," she said. "And the safety signal is good too."
Luetkemeyer described a patient she cared for, knowing she couldn't give them remdesivir: "It's heartbreaking."
As physicians choose who gets remdesivir and who doesn't, doctors are to some extent flying blind. They want to give it to the patients who benefited most in the drug's large clinical trial, but the National Institutes of Health still hasn't published that study.
"We don't have a lot of data to work on," Walensky said, and "there's not a lot of history with this drug."
Lawmakers are also unhappy.
"A doctor making a life or death decision about how to allocate a limited amount of this drug and which patient gets it and which doesn't -- the clinical trials are very important in that regard. They haven't made that available," said Rep. Lloyd Doggett, the Texas Democrat who chairs the House Ways and Means Health Subcommittee.
In a statement, the National Institute of Allergy and Infectious Diseases told CNN that "the study team is currently reviewing the available data for the [clinical] trial and plans to publish a preliminary report of the initial results in the next few weeks."
Walensky said some doctors in her hospital have also turned down offers of remdesivir for their patients. Those patients appear to be on the mend, she said, and the doctors don't want to give them a new drug with limited benefits and so little history.
In a Washington Post op-ed last week, Walensky and others from Mass General said remdesivir has left doctors with more questions than answers.
"In the wake of this media bombshell and data tease," they wrote, "we are left with a treatment that the FDA has permitted us to use, and that patients and families will justifiably expect, but with an extremely limited drug supply and no evidence-driven guidance on how to use it."
Walensky said using a committee to choose which patients get the drug "is not how we like to practice medicine." But with so many patients -- and so little remdesivir -- the hospital decided it was the most equitable approach.
Equitable, though, doesn't mean easy, especially when it's unclear who needs the drug most. "It's a nearly impossible situation when your overarching mission is to do right," Walensky said.