Federal officials are disappointed to find that the monoclonal antibody drugs they've shipped across the country aren't being used rapidly.

These drugs are designed to prevent people recently diagnosed with COVID-19 from ending up in the hospital. But hospitals are finding it cumbersome to use these medicines, which must be given by IV infusion. And some patients and doctors are lukewarm about drugs that have an uncertain benefit.

The Food and Drug Administration granted emergency authorization in November to two monoclonal antibody products — one produced by Eli Lilly, the other by Regeneron. President Trump was given the Regeneron product on an emergency basis before the FDA authorized it for widespread use.

These drugs mimic natural antibodies. They target the coronavirus that causes COVID-19 and are designed to block it from entering cells. The drugs are not effective in treating people sick enough to be hospitalized, but the companies' studies suggested that the drugs can help hold a new infection in check.

Charles Barnes, a 72-year-old Vietnam veteran from Upper Marlboro, Md., gave one a try. Before Thanksgiving, he came down with symptoms of COVID-19 – a stubborn cough and some chills.

"It got pretty bad one day," Barnes says, "but other than that I just had mild symptoms."

He and his wife got tested for the coronavirus. He came back positive. As it happens, the MedStar Health system where he got diagnosed had just started offering patients treatment with monoclonal antibodies.

"They kind of explained the science behind it a little bit, so I went for it," he says.

MedStar had set up a dedicated infusion center at its Washington Hospital Center, an easy drive from Barnes' home. Since patients like him are infectious, the hospital set up a system to escort patients to and from the infusion center to limit exposure to others in the hospital.

The treatment took an hour, he says, and nurses kept an eye on him for another hour to make sure there were no problems. "And there were no side effects, so I got into my car and drove home."

Barnes is one of 96 patients who had been treated by the Medstar Health system in the Washington, D.C., region as of mid-December. Dr. Princy Kumar, who is helping coordinate that effort, says the system could handle more cases. The biggest barrier is getting people to the hospital to get the infusion.

"As they are infectious, they can't just hail a ride-sharing app and show up at the infusion center," Kumar says. "And many of them are reluctant to put a family member, who has to ride with them in the car, at risk. So that's what we've identified to be our main challenge."

Kumar says, ideally, nurses would be sent to people's homes for treatment, "but that itself is a challenge because we are so constrained right now with the number of nurses and other nursing personnel we have right now because our hospitals are brimming with [COVID-19] patients."

As of last week, about 3% of patients who received the treatment ended up in the hospital anyway, Kumar says. Another 4% made a trip to the emergency room. Kumar figures that patients with similar preexisting conditions would end up in the hospital 10% to 15% of the time — so it appears the medicines are allowing some people to recuperate at home and reducing the burden on hospitals.

The buildup for these drugs — including Trump's glowing appraisal after he received one of them — led many to expect that the nation would be facing a dire shortage.

That's not how it's playing out in many places.

The federal government has purchased 1.2 million doses of these drugs and allocated more than 300,000 of those doses to states and territories. But Dr. Moncef Slaoui, chief adviser to the federal government's Operation Warp Speed, says initial surveys suggest only 5% to 20% of the drug that has been delivered has actually been used.

People over 65 or those with preexisting conditions such as obesity are eligible for the drugs, which means hundreds of thousands of people could potentially be in line to get them every week.

"We really hope to see a much, much higher level of usage," Slaoui said at a news briefing on Wednesday. "Really, this not acceptable."

"I'd say right now we're well below where we could be — if need be," says Dr. Peter Newcomer, chief clinical officer at University of Wisconsin Health in Madison. His hospital has been treating about five patients a day, and they have enough drug to treat a lot more than that. "The good news is we can give this infusion to anyone who qualifies and who asks for it," Newcomer says. "The bad news is we would like more people to call."

But the hotline to find out about treatment has been relatively quiet. The health system tried to bolster interest in early December through a blast of local TV stories, but Newcomer acknowledges that didn't move the needle.

The story isn't much different in western Pennsylvania. The University of Pittsburgh Medical Center has equipped 10 infusion centers in the region. Dr. Ryan Bariola says staffing was one big challenge since nurses are in high demand for inpatients. Another is that people have to be treated within 10 days of their first symptoms. Often many days elapse between symptoms and a positive test, which is necessary for treatment.

Some patients just give up. "Twenty [percent] to 25% of our patients are declining" to take the drug, Bariola says, even after they've been deemed eligible, talked to their primary provider and been offered an appointment. That's "either because they now feel better or they've thought about it further."

And some of the doctors in the system aren't so enthusiastic about it either. That may in part be because treatment guidelines issued by the National Institutes of Health say there isn't enough evidence to show whether the drugs actually work.

Among providers in his health care system, "of course everybody's focused, rightly so, on the vaccine right now," Bariola says. "So, we're trying to get their attention."

Doctors hope that as word gets out, more people will end up trying these drugs. They are provided to health systems free by the federal government, but it costs money to administer the medication. At first, Medicare set a price that would require many patients to pay a $60 copay, but the Centers for Medicare and Medicaid Services later found a way to waive that fee.

"Some of the private payers have not yet said if they are going to charge copays or not," Bariola says.

Stories such as Barnes' could make a difference, too. He heads up a 10-piece musical ensemble called the C. Barnes Project and, having recovered from COVID-19, is back to playing the trombone.

"As a matter of fact, a couple of days ago I did take it out of the case to see how my wind was, and it was the same. No difference," Barnes says.

And he says he's also back to his regular exercise regime. His case of COVID-19 is now just another story for him to tell.

You can contact NPR science correspondent Richard Harris at[email protected].

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