Nearly 90 cruise ships experiencing COVID-19 outbreaks are under investigation or observation by the Centers for Disease Control and Prevention.

The CDC did not say how many COVID-19 cases have been reported on board the ships, The Associated Press reports. Some of the vessels have been turned away at foreign ports, including the Carnival Freedom, which was denied entry to Aruba and Bonaire after it was reported that it is carrying sick passengers and crew members.

At the start of the pandemic in the spring of 2020, some cruise ships were forced to wait off the coasts of Florida and California, as officials were concerned about welcoming passengers and crew infected by the virus. After being shut down for months, the industry started to make its comeback in June, with cruises once again resuming in North America. 

The CDC has not said if it will enact any changes because of the new outbreaks, and no cruise lines have said they will stop running. Most require adult passengers to show proof of vaccination against the coronavirus. CDC spokesperson Jasmine Reed told AP the agency “acknowledges that it is not possible for cruising to be a zero-risk activity.”

Florida is a hub for cruise ships, and with the highly contagious Delta and Omicron variants both in circulation, the state is seeing its COVID-19 numbers rise. On Tuesday, Florida reported 46,900 new COVID-19 cases in one day, a new record. Hospitalizations are also up, with 3,400 patients in the hospital on Wednesday compared to 1,200 patients two weeks ago. This is not as bad as in late August, when five times as many people were hospitalized amid a Delta surge.