Upper East Side Legionnaires' Cluster Climbs to 28 Cases, 21 in Hospital

City health officials say a widening cluster of Legionnaires' disease on Manhattan's Upper East Side now stands at 28 confirmed infections, and 21 of those patients have needed hospital care.

The New York City Health Department has traced the cases to three ZIP codes — 10028, 10128 and 10075. So far, nobody has died.

Anyone who lives or works in those neighborhoods, or who has spent time there since late June, is being urged by officials to watch for symptoms and to get medical attention if they start feeling sick.

Legionnaires' disease is a form of pneumonia triggered by Legionella bacteria, which flourish in warm water. People who contract it can develop a cough, fever, muscle aches and trouble breathing.

Health officials stressed that the investigation has nothing to do with any building's plumbing. Residents can keep drinking tap water, bathing, showering, cooking and running their air conditioners at home without concern, the department said.

The illness also does not pass between people — it is not contagious.

Certain groups face elevated risk, according to the department: adults 50 and older, smokers and vapers, and people with chronic lung conditions, weakened immune systems or on immune-suppressing medications.

Investigators believe the likely culprit is a cooling tower somewhere in the affected area, and the agency is testing cooling towers throughout the neighborhood.

The cluster comes on the heels of last summer's Legionnaires' outbreak in Central Harlem, which infected more than 100 people and claimed seven lives.