Four dozen test positive for COVID-19 aboard world's biggest cruise ship

Nearly 50 people aboard a Royal Caribbean cruise ship tested positive for coronavirus when the ship returned to Miami on Saturday, according to a report.

All but one of the 48 infected passengers were fully vaccinated, according to a statement from the cruise line, and all passengers entered quarantine upon receipt of positive results.

"Everyone who tested positive was asymptomatic or had mild symptoms, and we continuously monitored their health," Royal Caribbean told NBC Miami.

The ship, which departed on Dec. 11, had 6,091 passengers aboard, 95% of whom were fully vaccinated – the cruise line requires passengers over the age of 12 to be fully vaccinated. Unvaccinated kids are required to obtain two negative COVID-19 tests before boarding the ship.

The Symphony of Seas is the world's biggest cruise ship.