As the coronavirus pandemic has dragged on, help has come in many forms. Some people have donated their federal recovery checks to charities and non-profit groups. Others have joined in neighborhood-based mutual aid efforts, helping deliver food and other essentials to needy neighbors.

But D.C. resident Beth Jacob has something even more valuable than time or money to give: her blood.

“After recovering, we just feel this immense sense of gratitude and relief,” she says, referring to her family’s brush with COVID-19, the disease caused by the coronavirus. “And for me, it just felt like I wanted to do anything I can. I want to drive and bring groceries to people. I want to do all the things with this potential newfound immunity. So the plasma seemed like the right thing to do.”

Of the close to 3,000 people in D.C. who have reportedly contracted the coronavirus so far, Jacob, 45, counts herself as one of the fortunate ones who has made a full recovery. (There are almost 23,000 confirmed positives in Maryland and Virginia.) She, her husband, and their two kids contracted the disease in March, with each showing different degrees of the symptoms—fever, body aches, exhaustion, and dry coughs. They’ve since been symptom-free, and have been cleared by the D.C. Department of Health.

Along with relief for Jacob and her family, the recovery brings with it a bloodstream full of antibodies that were created during her body’s fight against the coronavirus. And it’s those antibodies that are seen as a potential therapy for people still fighting the disease.

Hospitals, clinics, and blood banks are increasingly asking COVID survivors to consider donating their blood, in hopes of drawing out the antibodies and putting them to work in other people’s bodies.

“There has been probably for 100 years this idea that you could share one person’s immunity to the disease with another person who’s currently sick, and that’s in the form of convalescent plasma. And plasma is the liquid part of blood that contains immune proteins,” says Dr. A. Whitney Brown, a transplant pulmonologist at Inova Fairfax, which earlier this month put out a call for plasma from people who have recovered from the coronavirus.

“The idea is to take the liquid part of blood, or the plasma, from people who have recovered successfully from COVID-19, who are back in good health and have them donate it to be therefore used as a treatment, like a transfusion into someone who’s currently very ill,” she adds. “To borrow their immunity, so to speak.”

Plasma was used during the 1918 flu pandemic and has also been put to use in fighting infectious diseases like measles and diphtheria. Despite its long history, plasma therapy is in its early research phase for COVID; it was only in mid-April that the Food and Drug Administration laid out guidelines for doctors, researchers and hospitals to seek donations for use in current patients. The American Red Cross is now soliciting plasma from survivors, as are the National Institutes of Health. And in Maryland, Johns Hopkins University has been researching the use of convalescent plasma since late March.

Inova has gotten approval from the FDA to use plasma on multiple patients, part of a broader array of clinical trials being conducted to test different therapies and drugs on COVID patients.

Brown says one plasma donation has already been taken, from which three units of plasma were drawn and given to two patients at the Fairfax hospital last week. “And they are reported to be improving,” she says. “It’s not a cure. It’s not miraculous. But they have had an improvement in some of their clinical parameters.”

The challenge that Jacob and others who have recovered from COVID have experienced, however, is qualifying to donate their plasma. Jacob was told she has to wait 28 days after the last time she showed symptoms of the disease before she’s eligible to donate. For others, they were told to wait two weeks—but they need to show proof of a negative test, which can be hard to come by.

Brown says Inova is screening patients, and once they’ve been symptom-free for 14 days, the hospital will do a follow-up test to determine whether they have fully recovered from the disease. Jacob says she’s getting her follow-up test this week and hopes to donate plasma after that.

D.C. resident Kim Bender, 41, came down with COVID in March; she thinks she was on the earlier end of the pandemic’s arrival in the region. She’s since recovered, and has signed up with the Red Cross for the chance to donate her plasma. She’s still waiting for the chance to do so, but says that in a time of such medical uncertainty around the disease, it’s the least she can do to help.

“Can the fact that I got it early mean that I am able to help other people from getting it or from having it be a death sentence?” she says. “If it ever became a thing where people who already had it could be of use in hospitals because we have some level of immunity, I would love to do that just to make this suck a lot less for the world.”

This story originally appeared on WAMU.