A US Navy investigation into the spread of the coronavirus aboard the Theodore Roosevelt aircraft carrier has found that about 60 percent of sailors tested had antibodies for the virus, two US officials told Reuters on Monday, suggesting a far higher infection rate than previously known. In April, the Navy and the Centers for Disease Control and Prevention (CDC) started conducting serology tests to look for the presence of specific antibodies that are created by the immune system’s attack response to the presence of the virus and remain in the blood for a period of time.