Passengers aboard cruise ships operated by both Carnival Corp. and Royal Caribbean complained in recent days about their trips being disrupted by COVID-19 outbreaks.

As of Tuesday, there were 89 cruise ships with COVID-19 cases reported, according to the CDC. All but three of those ships were under CDC investigation. Aside from Carnival
CCL,
-0.24%
and Royal Caribbean
RCL,
-0.27%,
COVID-19 cases also occurred on ships operated by Disney
DIS,
+1.57%,
Norwegian Cruise Line
NCLH,
-1.04%
and Viking Cruises.

“Protecting public health is a business imperative for the cruise industry,” said Bari Golin-Blaugrund, vice president of strategic communications and public affairs at Cruise Lines International Association, an industry trade group.

“Cases that have been identified on cruise ships in recent weeks consistently make up a very slim percentage of the total population onboard, and the latest data show that COVID-19 has occurred less frequently on cruise ships than on land, with a greater proportion of asymptomatic or mild cases,” Golin-Blaugrund added. She noted that a ship could become subject to CDC observation if 0.1% or more passengers or even a single crewmember had tested positive within the last seven days.

Also see: ‘They think $100 per room is enough compensation?’ Caribbean cruise denied entry by ports due to COVID-19 outbreak

In some cases, ships were not able to visit planned stops during the itinerary because of the COVID-19 cases among passengers. One passenger reported that she and her fellow travelers were only offered $100 per room as compensation for the inconvenience.

“Our enhanced health and safety protocols have proven to be effective in our sailings over the past year since we restarted guest operations. These include vaccinations, extensive testing, masks and much more,” said Carnival spokesman Roger Frizzell.

The surge in COVID-19 cases onboard cruise ships comes amid the broader wave of cases caused by the omicron variant of the virus that causes COVID-19. The variant is believed to be more easily transmissible than previous forms of the virus.

It’s the latest blow for the cruise line industry, which has struggled to recover after being shut down by public-health officials at the height of the pandemic. Early in the COVID-19 pandemic, some of the most prominent outbreaks occurred on cruise ships. In the months that followed, many countries prohibited ships from docking because of concerns about the virus’ spread. Other cruise lines had deaths from the coronavirus on board and, as the industry suspended services, shares of cruise lines plummeted.

When cruise lines resumed operations this year, most began requiring passengers to be vaccinated against COVID and to provide proof of a negative COVID test. Other changes were also made to the cruising experience to reduce the possibility of transmission.