(CNN) — More than two dozen cases of Covid-19 have been detected among crew and passengers aboard a Carnival cruise ship, according to the Belize Tourism Board.
One passenger and 26 crew members tested positive prior to calling on the port in Belize City, a news release from the tourism board said. All 27 infected individuals are vaccinated and most are asymptomatic, according to the release.
Belize tourism officials met virtually with Carnival Vista officials on Tuesday to discuss the situation before passengers disembarked in Belize City.
During that meeting, "the team at Carnival noted that all positive cases have been isolated and contact tracing has ended with no additional positive cases found, and that the infected crew and passenger do not pose a threat to guests, crew or frontline workers in Belize," according to the tourism board's news release.
Passengers were allowed to disembark in Belize for normal shore excursions with one additional precaution: All guests with a negative Covid-19 test were required to provide proof to Belize officials, with random testing for those without proof.
Carnival said in a statement that it is managing a "small number" of Covid cases on the current Carnival Vista voyage but declined to specify exactly how many.
A "small number of positive cases" was also reported by the cruise line on the previous sailing of Carnival Vista out of Galveston, Texas. That prompted the company to institute its new fleet-wide mask rule for all passengers in certain indoor spaces a few days early on that Carnival Vista sailing.
"Guests on board the July 31 and August 7 sailings were notified and kept updated, and the CDC and destination officials have been apprised," the company said of the recent Covid cases.
All unvaccinated guests aboard the current sailing were set to be tested on Friday, prior to disembarking on Saturday, Carnival said. The company also randomly tests a large percentage of its vaccinated crew on a rotating basis and has tested more than 900 crew members since last Saturday, according to its statement.
Stepping up rules as the pandemic evolves
The Belize Tourism Board noted that additional protocols, including the use of N95 masks by crew and the closure of crew social areas, were implemented aboard the current voyage.
"The health, safety and well-being of our guests, crew and the destinations we visit is our priority. All activities on the ship are taking place and our guests have been terrific at adapting to our new protocols," Carnival said, noting that its safety protocols go beyond the US Centers for Disease Control and Prevention's guidelines.
Belize Tourism Board reported that crew on the ship are 99.98% vaccinated and passengers are 96.5% vaccinated. Those figures meet the CDC requirement for 95% of both crew and passengers to be vaccinated in order for a ship to sail without first conducting a trial cruise to test Covid safety measures.
In addition to the policy introduced last week requiring all guests, even those who are vaccinated, to wear masks in certain indoor areas, Carnival is stepping up its testing rules, requiring all guests to present a negative Covid-19 test result prior to embarkation. That policy goes into effect on August 14.
The rapid spread of the Delta variant has seen an uptick in reported cases of "breakthrough" infections in vaccinated people. Vaccinations have been highly effective at preventing serious illness, but they are not 100%.
Belize officials and the cruise line indicated that their safety protocols anticipate Covid-19 cases and are working as designed to mitigate risk when cases are detected.
Carnival Vista's August 14 voyage will sail as planned, Carnival said.