TAMPA (WFLA) – The Centers for Disease Control and Prevention on Thursday issued an advisory urging all travelers — vaccinated and unvaccinated — to avoid cruise ship travel amidst a record-breaking Covid surge driven by the omicron variant in many states across the United States.

“Even fully vaccinated travelers may be at risk for getting and spreading COVID-19 variants,” the CDC said in a midday bulletin.

The CDC said the travel health notice upgrade from level 3 to level 4 “reflects increases in cases onboard cruise ships since identification of the Omicron variant.”

They said more cruise ships are at “level yellow” on a color-coded CDC chart, at which point the public health agency investigates the Covid outbreak on the ship.

The U.S. Centers for Disease Control and Prevention is investigating more cruise ships due to new cases of COVID-19 as the omicron variant drives extremely high infection levels in the industry hub of Florida.

Cruise lines have not announced any plans to halt cruising.

Some cruise ships have not been allowed to disembark in Mexican ports due to cases reported, bringing to memory the early days of the pandemic when cruise lines negotiated docking plans as ships were being turned away by officials worried about the virus’s spread.

The Mexican government said Tuesday it would allow cruise ships with reported coronavirus cases to dock. The country’s Health Department said passengers or crew who show no symptoms will be allowed to come ashore normally, while those with symptoms or a positive virus test will be quarantined or given medical care.

NBC News and The Associated Press contributed to this article.