Norwegian Cruise Line (NCL) sent letters to passengers warning them that three prior passengers on the Norwegian Prima came down with Legionnaires’ disease. The letters, which were shared on reddit, state the sick passengers sailed on the Norwegian Prima in May and July 2026.
Legionnaires’ disease is a deadly type of pneumonia caused by the Legionella bacteria. Symptoms include fever, cough, headaches, muscle aches, and shortness of breath, according to the CDC. Symptoms usually develop 5 to 6 days after exposure to Legionella bacteria, with a range of 2 to 14 days. The disease has a fatality rate of 10% per the CDC.
The letter states the source of infections is unknown and that NCL is working with the CDC to test Norwegian Prima’s water system for Legionella bacteria. The letter does not state when the passengers got sick, whether during or after their cruises.
Hot tubs and private “balcony heated whirlpools” have been closed on the ship until the investigation is complete. In 2024, the CDC published a report stating private hot tubs were the likely source of Legionnaires’ disease outbreaks on two unnamed cruise ships.
So far, all tests on the ship’s water systems have come back negative according to the letter.
The full letter dated August 29, 2026 can be read below.
This is not the first time Legionnaires’ disease has been connected to the Norwegian Prima. Two passengers got sick with Legionnaires’ disease after sailing on the ship in November 2022, according to a letter sent by NCL.
In December 2025, two passengers fell ill with Legionnaires’ disease after sailing on the Norwegian Encore.
In both cases, NCL never publicly confirmed if the source of Legionnaires’ disease cases was from its ships’ water systems. NCL will likely follow the same playbook it has in the past for the recent Legionnaires’ disease cases: warn passengers of the disease but emphasize the source is unknown and never publicly follow up after that.