Legionnaires' disease outbreak in New York City's Upper East Side grows to at least 28 cases

New York City health officials say the Legionnaires' disease outbreak on the Upper East Side has grown to at least 28 confirmed cases, widening a response centered on cooling-tower testing and disinfection.

The cluster is affecting residents and workers in Carnegie Hill and Yorkville, where officials say contaminated cooling towers are the likely source. Health officials are urging anyone who has spent time in the area and is now experiencing flu-like symptoms to seek medical care.

How the outbreak has developed

Earlier AP reporting on July 6 put the total at 23 cases and 17 hospitalizations. By July 9, later reporting said the outbreak had climbed to at least 28 cases, showing that the cluster continued to expand as investigators worked through the neighborhood.

That growth has come as the city stepped up building inspections and disinfection orders. According to later reporting, roughly 160 cooling towers have been tested and 19 buildings with positive results have been ordered to disinfect.

City officials have not publicly identified a confirmed source tower or towers. For now, they are treating contaminated building cooling systems as the most likely origin.

Why cooling towers matter

Legionnaires' disease is not spread person-to-person. It is contracted by inhaling water droplets contaminated with Legionella bacteria.

Cooling towers and other building water systems can create the kind of aerosolized droplets that allow the bacteria to spread. Warm weather can make that risk more acute when systems are not properly maintained.

Public health response

The New York City Department of Health has focused on testing cooling towers and disinfecting buildings in the affected area. The response is aimed at identifying and removing any source that could continue exposing residents, workers and visitors.

The city’s message to the public is straightforward: people who spent time in the Upper East Side area and later develop fever, cough, shortness of breath or other flu-like symptoms should get checked promptly.

What remains unclear

Officials have not yet said which tower or towers are definitively responsible, and the latest reporting does not provide a new total for hospitalizations or any deaths. That leaves the investigation open even as the case count rises.

The outbreak also comes against a broader backdrop of recurring Legionnaires' clusters in New York City, where investigators have repeatedly had to trace illnesses back to building water systems.

For now, the main priority is containment. City inspectors are continuing to test, disinfect and follow up on affected buildings while monitoring whether additional cases are confirmed.