MANHATTAN — At least 46 people have been sickened in a Legionnaires' disease outbreak on the Upper East Side of Manhattan that began on July 2. Twenty-two of those infected have been hospitalized, and no deaths have been associated with the current outbreak.

The outbreak is concentrated in ZIP codes 10028, 10128, and 10075, covering the Carnegie Hill, Yorkville, and Lenox Hill neighborhoods along the east side of Central Park from approximately East 76th Street to East 97th Street. More than 100 New York City Health Department staff members have worked on the outbreak response since July 2.

Health Department officials have sampled water from at least 139 of the 160 cooling towers registered in the affected areas. They have identified 19 buildings as "buildings of interest" because their cooling towers preliminarily tested positive for Legionella bacteria. All 19 buildings have been ordered to drain, clean, and disinfect their towers immediately. Mayor Zohran Mamdani stated he would release the addresses of all buildings whose cooling towers test positive for Legionella during the initial screening process. "When there's a public health threat, New Yorkers deserve urgency and transparency from our government," Mamdani said. "That's why we're using every tool available to protect people by moving quickly to identify potential sources of exposure, requiring immediate remediation and making sure New Yorkers have the information they need to keep themselves and their families safe."

New York City Health Commissioner Alister Martin linked the outbreak to broader environmental trends, saying, "This is now a subtropical climate." He added, "It is absolutely true that climate change is worsening our exposure and increasing the propensity for legionnaires' disease clusters like we're seeing today." The Health Department also cautioned that disinfecting a cooling tower before a sample has been collected makes it impossible to trace whether that tower was the actual source of illness. New York City Council Speaker Julie Menin criticized the pace of the city's response, stating, "It is shameful to wait, to continue to wait, while we know more and more people every single day are getting sick and potentially can die of this disease." She urged immediate action, saying, "We have to prophylactically disinfect and that is what I'm urging the Health Department to do immediately."

Officials emphasized that it is safe to drink tap water, shower, cook, and use air conditioners in the affected areas. Legionnaires' disease is caused by the bacterium Legionella pneumophila and is contracted by inhaling mist containing the bacteria, often from cooling towers. The disease is not transmitted from person to person.

Symptoms include fever, chills, muscle aches, cough, headaches, and shortness of breath, and typically develop two to 14 days after exposure. Adults aged 50 and older, smokers, and people with chronic lung disease or weakened immune systems face the highest risk. Emergency Medicine Physician Benjamin Wyler advised residents, "The advice I would give to the average resident of New York City – don't live in fear of this. But if you're developing symptoms like a febrile illness and cough, or malaise, gastrointestinal issues, you should maybe have a lower threshold to seek care."

Under city regulations, building owners are required to register cooling towers and conduct Legionella sampling and compliance inspections every 90 days when the tower is operating. It takes approximately two weeks to grow Legionella samples in a lab to determine if the bacteria are viable.