The New York City Department of Health is investigating a cluster of Legionnaires’ disease cases on Manhattan’s Upper East Side, with 23 confirmed infections and 17 hospitalizations reported as of Tuesday.

Health officials said the cases have been linked to the Carnegie Hill and Yorkville neighborhoods. No deaths have been reported.

Legionnaires’ disease is a serious type of pneumonia caused by Legionella bacteria, which can grow in warm water systems. People can become sick after inhaling water droplets or mist that contain the bacteria. Officials emphasized that the disease is not spread from person to person.

The Health Department said the current investigation is ongoing as officials work to identify the source of the outbreak and reduce the risk of additional cases.

While the cluster is centered on the Upper East Side, residents in other boroughs may recall similar investigations in recent years. Last year, health officials examined Legionnaires’ disease cases reported in the Bronx neighborhoods of Highbridge and Parkchester.

Authorities stressed that the current outbreak is not linked to a building’s plumbing system and that it remains safe to drink tap water, shower, bathe and use home air conditioning units.

People at higher risk of severe illness include adults age 50 and older, smokers and individuals with weakened immune systems.

Common symptoms of Legionnaires’ disease include fever, chills, muscle aches and cough. Some patients may also experience headaches, fatigue, loss of appetite, confusion or diarrhea.

Health officials are urging anyone who lives in, works in, or has recently visited the Upper East Side and is experiencing symptoms such as fever, cough or difficulty breathing to seek medical attention promptly.

The Department of Health said early diagnosis and treatment can help reduce the severity of the illness and prevent complications. The agency continues to monitor the situation and provide updates as the investigation progresses.