Thanks for the CV location list -- which I didn't know before. The deployment history shows that USS Roosevelt embarked from San Diego on Jan17, and had a port of call at Guam from Feb7 to Feb10. After discovering COVID on the ship, it returned to Guan on Mar27.
So, the Roosevelt sailors were either infected at San Diego before Jan17, or got infected at Guam in Feb7-Feb10. Did Guam report COVID cases that occurred before the Roosevelt's February port of call? (If so, where did those Guam cases come from?) If Guam didn't report COVID cases, then we must conclude that the virus was present at the San Diego base in mid January or earlier. And if it was in San Diego, when did it get there, and where did it come from?
This is indeed a very interesting case, since the carrier's deployment history gives us precise dates for isolating when the virus got on board the ship. And more broadly, it can fill in the timeline for COVID cases on US territory.