(The Hill) – More than 40 passengers aboard a Royal Caribbean Symphony of the Seas cruise ship have tested positive for the novel coronavirus, USA Today reported

The cruise line confirmed that 48 out of 6,074 passengers and crew members had tested positive for COVID-19 on the cruise, which ended in Miami on Saturday. 

Initially, the cruise line reported 44 cases on board. “This number (48) includes four additional close contacts which were identified as COVID-19 positive at the end of the voyage,” Lyan Sierra-Caro said Monday. “The guests were quarantined on board and assisted upon the ship’s arrival on Dec. 18.”

All passengers 12 and older were required to be fully vaccinated and to test negative to board the Symphony of the Seas ship. The ship sailed with 95% of the onboard community fully vaccinated on the Dec. 11 to Dec. 18 cruise, with 98% of those people who tested positive being fully vaccinated, Royal Caribbean told USA Today.

Sierra-Caro also said the 48 passengers were identified through contact tracing after a lone guest tested positive and then quickly quarantined, USA Today reported. 

“We were notified by the (Centers for Disease Control and Prevention) that a guest on board our (December) 4th cruise tested positive and it was identified as omicron,” Sierra-Caro said Saturday. “They (CDC) asked us to notify guests on the sailing — the one that ended today — and the current one.”

“Everyone who tested positive is asymptomatic, and we continually monitored their health. Six guests were disembarked earlier in the cruise and transported home. The remaining guests received assistance today upon our arrival,” Sierro-Caro said.  

Initially, Royal Caribbean said that everyone who tested positive was asymptomatic. In the statement Monday morning, it said that “everyone who tested positive were asymptomatic or had mild symptoms, and we continuously monitored their health.”

Dozens of U.S. states, including Florida, have now reported cases of the omicron variant, and public officials across the country are reconsidering public health measures to guard against its spread. 

In a statement, the Centers for Disease Control and Prevention confirmed it is aware of the situation on the Royal Caribbean cruise ship, saying it is “working with RCI to gather more information about the cases and possible exposures, and RCI will be collecting specimens from the current voyage for genetic sequencing.”