A passenger tested positive for COVID-19 Wednesday on SeaDream Yacht Club’s SeaDream 1, the first cruise in the Caribbean since March, sending crew and passengers scrambling to isolate, according to The Points Guy. Reporter Gene Sloan, who is aboard the ship, said SeaDream’s protocol required its 53 passengers to test negative for COVID-19 twice, one several days before boarding and again on boarding day. The ship’s captain told passengers that the infected person had felt ill before the test, and the crew was now assuming that it had one or more positive cases on board. Passengers were set to be tested a third time on Wednesday using rapid test machines, which can be less accurate than PCR tests.

The captain said the ship would immediately return to Barbados, bringing an end to the cruise. It had visited St. Vincent and the Grenadine islands of Canouan and Tobago Cays, but had not come into contact with any locals. Barbadian health authorities were set to board the ship to test passengers and crew as of Wednesday, with the possibility of testing being deferred to Thursday morning.