Passengers that sailed on a recent Royal Caribbean cruise received an email this week to alert them of a possible case of Legionnaires' disease.
The email was sent by the cruise line to people that went on Symphony of the Seas May 9th sailing from Cape Liberty, New Jersey.
In the email, it says Royal Caribbean was alerted by the U.S. Centers for Disease Control (CDC) of someone that went on Symphony and later was diagnosed with Legionella.
"Your health and safety are always our top priority, and we are reaching out for your awareness," the email said.
"The CDC has advised that while they are unsure where exposed, a guest who recently sailed on Symphony of the Seas, was later diagnosed with Legionella. As a precautionary measure, we implemented heightened sanitation protocols and followed all CDC guidance."
Royal Caribbean went on to advise that Legionella cannot be spread from person to person.
"It's important to know that Legionella is not contagious from person to person. It is contracted by inhaling water droplets from a source containing the bacteria, which can be found throughout the world in any environment containing water - ponds, lakes, rivers, and streams, as well as municipal water systems, fountains, and whirlpools. Most healthy people exposed to Legionella do not get sick."
Symptoms of the infection include cough, shortness of breath, fever, muscle aches and headaches.
Similar emails were sent earlier this year
Royal Caribbean has sent emails about a passenger that sailed on Symphony of the Seas and later had Legionnaires' disease.
The first such email went out in January when two unrelated passengers on the ship were sickened after their cruise.
One of the passengers had sailed on the ship in October 2024, while the other sailed in December 2024, according to the CDC.
Then in April 2025, more emails were sent to passengers that sailed on Symphony between March and April.
In all the emails sent, the CDC never said the cases originated on the ship.
There's no record of any confirmed disease aboard Symphony of the Seas that has been reported to the CDC.
It's possible the people had Legionella before they ever boarded a cruise ship, or they contracted it after the cruise somewhere else.
How Legionnaires' disease spreads
Legionnaires' disease is a type of pneumonia caused by a bacteria called Legionella, but the truth is that it's actually pretty tough to catch.
The only way to get Legionnaires’ is by breathing in tiny water droplets that contain the bacteria. You can't get it by touching something someone who has is touched or breathing near them.
These droplets usually come from man-made water systems, such as large air conditioning units in commercial buildings, hot tubs that aren’t properly cleaned, decorative fountains, or even plumbing systems in big buildings like hospitals or hotels. But just being around those places doesn’t mean you’re going to get sick. The conditions have to be just right for the bacteria to grow and for someone to inhale enough of it to cause an infection.
And even then, most people don’t get sick.
In fact, Legionella is commonly found in freshwater lakes or rivers, and don't usually cause a problem. For the bacteria to make someone sick, it has to multiply in a man-made system where the water is warm (between 77 and 113 degrees Fahrenheit), and then that water has to be turned into mist that someone breathes in.
Even if you do breathe it in, you will most likely not get sick. Most healthy people exposed to Legionella do not get sick. The people most at risk are older adults, smokers, people with chronic lung problems, and folks with weakened immune systems.
