Legionnaires' disease outbreak in New York City reaches 46 cases with 22 hospitalizations

Jul 6, 2026

A Legionnaires' disease outbreak in New York City's Upper East Side has reached 46 cases, resulting in 22 hospitalizations. Health Commissioner Dr. Alister Martin and other experts warn that climate change is driving up infection risks. Officials have detected Legionella bacteria in 31 area cooling towers, prompting Mayor Zohran Mamdani to order rapid disinfection. While the current outbreak affects a wealthy area, leaders note the disease historically disproportionately impacts communities of color.

Upper East Side legionnaires' outbreak

▪A Legionnaires' disease outbreak in the Upper East Side neighborhoods of Carnegie Hill and Yorkville in New York City has grown to 46 confirmed cases.
▪The Upper East Side Legionnaires' disease outbreak is concentrated across three zip codes: 10028, 10128, and 10075.
▪At least 22 people have been hospitalized due to the Upper East Side Legionnaires' disease outbreak, with some patients admitted to the intensive care unit.

Climate change increases Legionella

▪Columbia University epidemiology professor Dr. Wafaa El-Sadr stated that warming temperatures from climate change could worsen Legionnaires' outbreaks.
▪New York City Health Commissioner Dr. Alister Martin stated that climate change is worsening exposure and increasing the propensity for Legionnaires' disease clusters.

Cooling tower contamination sources

▪New York City Health Commissioner Dr. Alister Martin reported that Legionella bacteria was detected in 31 cooling towers in the affected Upper East Side area.
▪The New York City Department of Health and Mental Hygiene believes the likely source of the Legionnaires' outbreak is a contaminated building cooling tower.

Building inspection orders

▪New York City Mayor Zohran Mamdani announced measures to publicly identify buildings suspected as Legionella sources and require rapid cleaning of cooling towers.
▪New York City Council Speaker Julie Menin expressed concern that the health department failed to proactively require disinfection of all area cooling towers.
▪New York City Health Commissioner Dr. Alister Martin signed orders for at least 19 buildings to drain, clean, and disinfect their cooling towers.

Racial health disparities

▪Multiple studies and past outbreaks in New York City show that Legionnaires' disease disproportionately affects Black Americans and people living in poverty.
▪Manhattan Community Board chair Marquis Harrison stated at a public meeting that past Legionnaires' outbreaks were primarily seen in Harlem and the South Bronx.

Outbreak investigation challenges

▪New York City Comptroller Mark Levine stated that growing Legionella samples in a laboratory takes approximately two weeks, delaying source identification.
▪Epidemiologists must culture water samples to find live colonies and sequence their genomes to match patient sputum samples to identify the outbreak source.