At least four cruise ships have reported COVID-19 cases in recent days, coming as Colombia officials prevented the Seven Seas Mariner ship from allowing anyone to disembark in Cartagena after seven positive cases were reported onboard. Authorities in Mexico also prevented the Holland America Line Koningsdam vessel from allowing passengers to disembark in the tourist area of Puerto Vallarta late last week after 21 crew members tested positive for the virus. Health authorities in Jalisco state, Mexico, were going to allow individuals who tested negative to leave the ship. But on Thursday, they changed their decision due to an “exponential growth of confirmed cases in the crew,” according to the department. The Holland America ship has a fully vaccinated crew and requires all passengers to show proof of vaccination before boarding, according to its website. Crew and passengers also have to present proof of a negative COVID-19 test. Seven Seas Mariner, which has a …