Health experts have found tentative evidence proving that patients seriously ill with COVID-19 can benefit from convalescent plasma collected from those who have recovered from the disease. The convalescent plasma initiative is one of the options scientists around the world are considering as they race to find potential treatments for COVID-19.

On Friday, the Food and Drug Administration announced that Mayo Clinic would lead the testing of the effectiveness of convalescent plasma in coronavirus patients. This type of treatment has been around for more than a century and was first used during the 1918 flu pandemic.

According to Mayo Clinic CEO Dr. Gianrico Farragio, convalescent plasma involves the collection of blood plasma from a recovered COVID-19 patient and the transfusion of the plasma into someone infected with the virus to see if the antibodies from the recovered patient can help the person ill with COVID-19 fight the disease.

Just this month, two teams of doctors working in two different hospitals in China gave antibody rich-plasma to 15 COVID019 patients and recorded striking improvements in their conditions. In one of the pilot studies, doctors found that virus levels in patients significantly drop after receiving convalescent plasma. Their symptoms also started to improve three days after receiving the plasma.

One of the proponents of the study, Xiaoming Yang of the National Engineering Technology Research Center for Combined Vaccines in Wuhan, said the convalescent plasma treatment is a “promising rescue option” for severely ill COVID-19 patients. However, he said a more comprehensive randomized trial was needed to confirm the findings.

If the treatment is proven effective, then it can be used to prevent patients from getting seriously ill with the novel coronavirus. According to Farrugia, it can also be given to people who are at risk of contracting the virus, including healthcare workers on the frontlines.

Currently, there are more than 100 sites working to implement convalescent plasma for patients. “That really speaks about the collaboration that is needed in a pandemic like COVID-19,” said Farrugia.

Coronavirus COVID-19 Doctors New York, USA Doctors test hospital staff with flu-like symptoms for coronavirus (COVID-19) in set-up tents to triage possible COVID-19 patients outside before they enter the main Emergency department area at St. Barnabas hospital in the Bronx on March 24, 2020 in New York City. New York City has about a third of the nation’s confirmed coronavirus cases, making it the center of the outbreak in the United States. Misha Friedman/Getty Images