On Sunday, President Donald Trump announced the emergency authorization of convalescent plasma for COVID-19 patients.

If you’ve already had COVID-19 and have recovered, you may be able to help those still battling the virus. Doctors are experimenting with a treatment that uses blood plasma from COVID-19 survivors.

More than half of blood is made up of plasma, which shuttles nutrients, hormones, and proteins to where they’re needed in the body. The plasma also houses antibodies - a type of protein made when your body detects a virus. Those antibodies then seek out and destroy the virus. 

After you recover, those antibodies remain in your blood plasma. If they detect that virus in the body again, they can eliminate it before it has a chance to make you sick.

Antibodies can be harvested from the donated plasma of recovered patients to create something called a convalescent serum, which can then be injected into a COVID-19 patient. The hope is that the donor’s antibodies help the sick patient’s body fight off the virus. 

It’s not a new idea. Convalescent serums have been used to treat people during other outbreaks, including the Spanish Flu in 1918 and SARS in 2002. The treatments have been shown to lower mortality rates until a better treatment or vaccine can be developed.

Since COVID-19 is an illness caused by a new virus, so far there’s only anecdotal evidence that the therapy works. Doctors are still experimenting with exactly when to administer the treatment and how much of the serum to give individual patients..

Prior to President Trump's announcement that the FDA authorized the emergency use of convalescent plasma treatment, it had only been approved by the FDA for compassionate use, meaning doctors could only give it to patients who have a severe or life-threatening case of coronavirus.

To be a plasma donor, you must have previously tested positive for COVID-19 but no longer be actively infected with it. This means you must now test negative and have  been fully recovered for 14 days prior to donation. You must also have a certain number of the COVID-19 antibodies in your system. A doctor will take a nasal swab to test this. 

If you are pregnant or have certain health conditions, you may not be able to donate. 

You can check the The Red Cross website for a complete list of donor requirements, or you can ask your doctor.  

Health officials plan to test the general population widely for the presence of antibodies. This will help officials get a better picture of how many people have already had COVID19—including, importantly, those without symptoms. It will also aid in determining when patients are free to return to work and other normal activities—and when they’re able to donate their plasma to those who need it.

To learn more visit the National COVID-19 Convalescent Plasma Project website or contact your local health department.