Claire Stobb hates needles. The 21-year-old says she can’t even remember the last time she had her blood drawn at the doctor’s office.

“Needles are so traumatizing for me, even getting a flu shot, but especially when there’s blood,” Stobb, of La Crosse, Wisconsin, said.

But after she was diagnosed with COVID-19 in March, she says she fought her fear and has now donated blood plasma four times over the last four months.

Doctors and health officials across the country are desperately urging COVID-19 survivors like Stobb to donate plasma, the yellowish, watery part of the blood that’s rich in proteins and antibodies.

So-called convalescent plasma, from people who have recovered from a particular illness, has been used for more than 100 years to treat patients with all sorts of viruses, including influenza and Ebola. The hope is that plasma from a COVID-19 survivor, filled with antibodies against the virus, could boost the immune systems of those who are now sick, helping them to fight off the illness, too.

“There is right now a lot of demand, and not as much supply,” Dr. Stephen Hahn, commissioner of the Food and Drug Administration, told NBC News. One doctor in Florida, for example, told him she’s ordering plasma infusions for COVID-19 patients as soon as they get to the emergency room.

Plasma donations were markedly high in May, after the first surge of coronavirus infections in the Northeast. But the number of donors has since waned while the need has soared, especially with the current wave of infections across the South and the West.

“There’s a huge spike in the U.S. of COVID cases who are hospitalized,” Dr. Scott Wright, lead researcher for convalescent plasma at the Mayo Clinic in Rochester, Minnesota, said. The Mayo Clinic is coordinating the FDA’s expanded access program for plasma, which allows doctors to use the treatment even though it has not been approved or authorized.

“We see twice to three times the rate of usage of convalescent plasma in July than we did in April in the U.S. as part of the expanded access program, suggesting that hospitals and doctors are comfortable and feel the need to use it more,” he said. “We need more donors or we’re going to run out.”

Donating plasma has been around for years and is safe to do, but it’s more time consuming and involved than simply donating blood. First-time plasma donors typically go through a lengthy safety check to make sure they don’t have other infections such as hepatitis or HIV. In some cases, they are required to meet with a doctor to screen them for illegal intravenous drug use.

Once the patient is cleared to donate, they are hooked up to a machine that takes out their blood and separates the plasma out, a process called apheresis. The rest of the blood is then transfused back into the patient, followed by saline to help the patient rehydrate since plasma is mostly made up of water.

“There’s a little pinch when they stick you with the needle, but it’s not unbearable, even for me, and I’m a little baby about it,” Stobb, who has been donating in her hometown, said. “I usually donate in the afternoon because it definitely knocks me out the rest of the day.”

This is a sacrifice of volunteerism, that if you wanted to make, can potentially save a life.

“This is a sacrifice of volunteerism, that if you wanted to make, can potentially save a life,” Hahn said.

Also complicating the process, donors must have COVID-19 antibodies. Antibodies don’t rise to sufficient levels until several weeks after a person is infected, and studies have found they typically start to decrease three to six months after recovering from the illness.

“We have a limited time opportunity to collect plasma from someone who’s recovered from COVID,” Wright said. “We have just a few months while they still have plasma with antibodies in it.”

While scientists are still waiting for more conclusive data on whether convalescent plasma is effective for treating COVID-19 patients, it’s being used extensively under an expanded use program in hospitals across the country.

According to Wright, more than 50,000 coronavirus patients at 2,700 hospitals have received plasma through the expanded access program. Early evidence suggests it may be effective in sick patients, but randomized controlled trials — the gold standard for medical studies — are still missing.

While the focus of plasma has been to treat sick patients, doctors at the Mount Sinai Health System in New York City are now calling for donors with high antibody levels to donate plasma that’ll be used to try and prevent COVID-19. (The reporter had COVID-19 in March and donated plasma at Mt. Sinai after recovering.)

Working with Emergent BioSolutions, scientists there are developing a therapeutic that’s highly concentrated with antibodies called hyperimmune globulin. Instead of a transfusion for sick patients, this would be an injection used for at-risk populations like health care workers and cancer patients.

“In advance of a vaccine, we could give them shots like this every 30 days,” Mt. Sinai President Dr. David Reich said.

The hope is to start clinical trials by late September or early October, he said. But they need to collect 3,000 liters of plasma first. So far, they have only collected 100 liters since their new plasma donation center opened three weeks ago.

Reich says it’s been harder to get donors now that the number of infections has dropped in New York.

“There’s a little fatigue with the constant anxiety related to COVID,” he said. “Back when people were locked down and there was nothing to do, it was very much top of mind. I think it’s just human nature to have some fatigue. You can see it with people not wanting to wear masks and young people violating social distancing rules. It’s just hard.”

But for Stobb, she says donating gave her a way to help others with a disease that we’re still learning so much about.

“There is something we can do,” she said. “It’s given me some control over what’s going on.”