The Centers for Disease Control and Prevention (CDC) on Tuesday said it is actively investigating or observing 86 cruise ships following COVID-19 outbreaks on board.

Why it matters: The Omicron variant has driven up infections across the U.S., upending vacation plans and disrupting travel. The new strain is the latest sign of the pandemic’s hold on the cruise line industry.

• The industry, which was an early epicenter for coronavirus outbreaks, staged a comeback in September, with several preventative measures in place to curb the spread of the virus.

Details: The CDC has started investigating 38 ships, and has already investigated 48 additional vessels, which remain “under observation,” according to its update.

• The affected cruise lines include Disney, Carnival, Royal Caribbean and Norwegian.

Worth noting: An additional three ships are being monitored by the CDC due to reported COVID infections, though case numbers are below the agency’s threshold to start an investigation — cases reported in more than 0.10% of passengers or a single crew member in the previous seven days.

What they’re saying: “The Cruise Lines International Association (CLIA) and our members … continue to have very productive dialogue and are working together with the CDC in the interest of public health and safety,” Anne Madison, a spokesperson for the Cruise Lines International Association, said in a statement.

• “Many of our members have announced additional measures in response to the Omicron variant, including strengthening testing, masking and other requirements, as well as encouraging booster vaccine doses for those eligible—and some cruise lines are requiring an additional test at embarkation,” she added.

Editor’s note: This story has been updated with new numbers from the CDC and comment from the Cruise Lines International Association.