Upper East Side Legionnaires' cases rise; inside Harlem's 2025 outbreak

Cases of Legionnaires' disease continue to grow in Manhattan's Upper East Side, sparking concerns amongst locals in the area as officials investigate.

But when was the last time something like this happened in New York City?

Just last year, an outbreak in Harlem claimed the lives of seven people, with over 100 cases reported in total.

Here's what to know on the city's current cluster, and how last year's outbreak happened.

Upper East Side Legionnaires' disease cluster

The city's health department said it is still investigating a community cluster in Carnegie Hill and Yorkville, two areas in the Upper East Side. The reported ZIP codes affected include: 10028, 10128, and 10075

As of July 6, the health department reported 23 cases, up from an earlier 18.

The city also said that 17 hospitalizations have been reported, too. No deaths have been announced from the current cluster.

Mark Levine, the city's comptroller, said that this current cluster of cases is from a contaminated cooling tower, and not a water system.

"All cooling towers in area are being sampled and tested in the NYC Public Health Lab," he wrote on X Sunday night. "It unfortunately takes several weeks for cultures to grow."

Harlem's 2025 Legionnaires' disease outbreak

Just last year, another outbreak happened in Harlem. It was one of the largest outbreaks New York City had seen in a decade.

In August, when the city closed the investigation, officials said that seven people had died, 90 had been hospitalized and 114 cases were reported in total. According to the Center for Disease Control and Prevention, about 1 out of every 10 cases of those who get sick with Legionnaires' disease "will die due to complications from their illness."

The city said that at least 90 percent of those in the Central Harlem cluster had fallen under increased risk factors, including those 50 and above, smokers or those having a weakened immune system.

After the testing of cooling centers, Legionella bacteria had been found in two locations: Harlem Hospital and a nearby construction site.

"We must ensure that we learn from this and implement new steps to improve our detection and response to future clusters, because public safety is at the heart of everything we do," then-Mayor Eric Adams said in a statement.

"This is an unfortunate tragedy for New York City and the people of Central Harlem as we mourn the seven people who lost their lives and pray for those who are still being treated."

What should residents do now?

People are at risk of getting Legionnaires' disease if they breathe in water vapor contaminated with the bacteria.

The health department emphasized that residents cannot get it through drinking water, cooking or from using AC units, and Legionnaires' disease is not contagious.

If you have flu symptoms and are from or have been in the area, city officials recommend seeking medical attention, particularly if you are more at risk.

This article originally appeared on USA TODAY: Upper East Side Legionnaires' cases rise; inside Harlem's 2025 outbreak

Reporting by Amethyst Martinez, USA TODAY NETWORK / USA TODAY

USA TODAY Network via Reuters Connect

Copyright Reuters or USA Today Network via Reuters Connect

This story was originally published July 7, 2026 at 7:16 AM.