The U.S. Centers for Disease Control and Prevention (CDC) announced on Thursday updates of its ongoing health and safety program for cruise ships operating in U.S. waters.

CDC declared that it'll decrease the percentage limit for determining "exceedingly immunized trips" from 95 percent to 90 percent of eligible passengers or those who are five or older. In any case, the vaccination rate of the crew must stay at 95 percent or more to be considered an exceedingly vaccinated voyage.

In addition, the CDC has announced that isolation rooms no longer need to have negative pressure. They must still be located in pre-determined areas, and the exception for transferring individuals to pre-determined cabins remains in force within 36 hours of disembarkation.

"The Cruise Lines International Association (CLIA) and its member cruise lines welcome the recent update to the Centers for Disease Control and Prevention (CDC) COVID-19 Program for Cruise Ships Operating in U.S. Waters," CLIA said in a statement on Thursday.

"The CDC's adjustment of vaccination and quarantine and isolation room requirements recognizes the highly protective measures in place onboard cruise ships and is in keeping with the CDC's lifting of any travel-related advisory against cruising. CLIA-member cruise lines continue to provide one of the highest levels of COVID-19 mitigation for the traveling public with higher-vaccination rates and higher frequency of testing than most any other setting. We look forward to the further development of the program to bring greater alignment across the travel and tourism sector," CLIA concluded.