Dec 6 (Reuters) - Since U.S. cruises resumed in June, travel and tourism operators have enacted vaccine and testing requirements to avoid disruptions that cost them millions of dollars for much of the pandemic. Even with these protocols, at least 17 people tested positive for COVID-19 on a Norwegian Cruise Line Holdings Ltd (NCLH.N) ship that disembarked in New Orleans recently, highlighting the challenges in curbing the spread of COVID-19 in confined spaces. One member of the crew has a suspected case of the Omicron variant. read moreTo be considered fully vaccinated, all the cruise lines require the final vaccine dose to be administered 14 days before the start of the cruise. All the cruise lines below require crew to be vaccinated. Here are their policies: Norwegian Cruise Line has a 100% vaccination policy, meaning children under 5 who are not yet eligible for a vaccine are not permitted on cruises. Norwegian tests its passengers for COVID at the port before they board. * Major Carnival Corp (CCL.N) and Royal Caribbean Group (RCL.N) brands require most passengers age 12 and older to be fully vaccinated but the companies do make some exceptions. Unvaccinated children under the age 5 can cruise on Carnival"s ships. Passengers must present a negative COVID test taken no more than two days before boarding. Royal Caribbean accepts antigen tests. * Walt Disney Co"s (DIS.N) Disney Cruise Line requires all passengers eligible for vaccines in the United States to be fully vaccinated. Starting Jan. 13, all guests ages five and up will need to be vaccinated. Unvaccinated passengers must show a negative COVID-19 test taken between three days and 24 hours before their sail date. Rapid antigen tests are not accepted. Everyone is tested by Disney Cruise Line at the terminal before boarding, meaning unvaccinated passengers are tested twice.