A U.S. Navy investigation into the spread of the coronavirus aboard the Theodore Roosevelt aircraft carrier has found that about 60 percent of the roughly 400 sailors tested had antibodies for the virus, three U.S. officials told Reuters on Monday.

All 4,800 sailors on the Roosevelt aircraft carrier were tested for the coronavirus previously, and about a quarter tested positive. But in April the Navy and the Centers for Disease Control and Prevention (CDC) started conducting a serology test to look for the presence of specific antibodies.

If sailors who did not test positive show antibodies, that could suggest a higher rate of infection than previously known. Similar tests in Italy and elsewhere have indicated the presence of antibodies in people who did not test positive previously, giving a more accurate sense of the spread of the virus.

However, the serology test could also show that people who tested positive for coronavirus do not carry antibodies later, potentially raising questions about their immunity to the virus.

The spread of the virus on the ship put into motion a series of events that led to the firing of the ship’s captain after the leak of a letter he wrote calling on the Navy to establish stronger measures to protect the crew.

One sailor from the ship died from the coronavirus and several others were hospitalized. But broadly, sailors, who are generally healthier and younger, fared better than the general population and most showed no symptoms whatsoever.

(SD-Agencies)