The treatment, an antiviral therapy called remdesivir, is thought to work by blocking the virus from reproducing itself in the body.

“It basically stops the production of the virus,” Dr. Gregory Poland, an infectious diseases expert and director of the Mayo Clinic’s Vaccine Research Group in Rochester, Minnesota, told NBC News…

“Treatment with intravenous remdesivir was initiated on the evening of day seven,” they wrote.

On day eight, the man’s condition started to improve. He was able to be taken off the ventilator and got his appetite back. His fever resolved and his cough slowly dissipated.