The USS Milwaukee is temporarily unable to sail after a COVID-19 outbreak among its “100% immunized” crew, the U.S. Navy said on Friday, without specifying how many sailors tested positive.

Driving the news: The Navy has not determined the variant of COVID and the sailors who tested positive are isolated from the rest of the crew. The ship is ported in Cuba’s Guantanamo Bay, less than two weeks after its deployment.

Be smart: “100% immunized” doesn’t necessarily mean that USS Milwaukee sailors received booster shots, as third doses are not yet required for active duty military.

Boosters “are not yet mandatory but recommended,” spokesperson Cmdr. Kate Meadows told the Washington Post. The ship also now has a strict mask mandate.