United States reports 15th case of coronavirus after a person under quarantine tests positive The Centers for Disease Control said on Thursday that a person under quarantine at a military base in San Antonio had tested positive for the virus, bringing the number of confirmed coronavirus patients in the United States to 15. The person, who was not identified, arrived at the base last week on a State Department-chartered flight and is now being treated in isolation at a hospital in the area. The patient is the third person under quarantine to test positive, joining two people at a base in San Diego who were confirmed to have the virus this week. In its statement announcing the case, the C.D.C. said that there would likely be more cases over the next few days and weeks. More than 600 people who left Wuhan after the outbreak began remain under required quarantine at military bases in the United States.