More than 500 clinical trials are under way world-wide in the race to find an effective treatment for Covid-19. Everybody wants it; nobody has it—yet. But one of the most promising therapies for Covid-19 patients uses “medicinal signaling cells,” or MSCs, which are found on blood vessels throughout the body.

In preliminary studies, these cells cut the death rate significantly, particularly in the sickest patients. With a powerful 1-2-3 punch, these cells eliminate the virus, calm the immune overreaction known as a cytokine storm, and repair damaged lung tissue—a combination offered by no other drug. This type of regenerative medicine could be as revolutionary as Jonas Salk’s polio vaccine.

In one pilot study in March, doctors at Mount Sinai Hospital in New York treated a dozen severely ill Covid-19 patients on ventilators with MSCs. Two infusions modulated their hyperactive immune systems, and 83% of those patients survived. With such promising results, the team at Mount Sinai and the supplier of the cells, Mesoblast Ltd., won Food and Drug Administration clearance and National Institutes of Health funding to conduct a randomized trial on 300 patients. The first patients in the trial received the treatment in early May.