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Here's what to know about the Legionnaires' disease outbreak on the Upper East Side
By Caroline Lewis - 7/6/2026, 5:32 PM - 826 words
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Here's what to know about the Legionnaires' disease outbreak on the Upper East Side
Cases of Legionnaires’ disease are mounting on the Upper East Side of Manhattan as city health officials work to identify the source of the outbreak, which was first announced late last week.
So far, 23 people have been infected with the severe form of pneumonia across three ZIP codes stretching from the Upper East Side to the East River: 10028, 10128 and 10075, according to the city health department.
No deaths have been reported so far.
Anyone who has visited the East Side of Central Park between East 76th Street and East 97th Street should also monitor their symptoms, “out of an abundance of caution,” the city health department said.
City officials say the current cluster is likely linked to mist contaminated with Legionella bacteria emanating from a water cooling tower in the area.
City officials are in the process of testing cooling towers in the affected ZIP codes for the bacteria and any towers that test positive will undergo remediation to remove the bacteria, according to the health department.
In the meantime, health officials are urging anyone who lives or works in the area, or has traveled there since late June, to keep an eye out for flu-like symptoms and visit a doctor right away at the first signs of illness.
Here’s what else you need to know about the outbreak and Legionnaires’ disease.
What are the symptoms of Legionnaires’ disease?
Symptoms of Legionnaires’ disease are similar to those that might emerge from other types of pneumonia and can include fever, chills, muscle aches, cough, difficulty breathing and gastrointestinal symptoms such as diarrhea, according to the city health department.
It can take anywhere from two days to two weeks for symptoms to develop after exposure to Legionella bacteria, according to the U.S.
Centers for Disease Control and Prevention.
Doctors across the city have been advised by the health department to be on high alert for the disease and to test for Legionnaires’ specifically if someone who has been in one of the affected ZIP codes presents with pneumonia-like symptoms.
Who is most at risk for Legionnaires’?
Most of the people who have tested positive for Legionnaires’ in the current cluster live on the Upper East Side, suggesting that those who spend the most time in the area are at higher risk of getting sick, Dr.
Alister Martin, the city health commissioner, said at a virtual town hall on the outbreak Monday evening.
In general, Legionnaires’ is more likely to affect people over 50 as well as those who smoke or vape, have a chronic lung disease or are immunosuppressed, according to the city health department.
Can UES residents still use AC and take a shower?
The short answer is yes.
Legionella bacteria can grow in buildings’ plumbing systems, but larger clusters such as the one emerging on the Upper East Side are typically linked to water cooling towers that emit mist into the atmosphere.
That means people in a larger geographic area are at risk of contracting the disease, but UES residents don’t have to take any particular precautions related to their buildings’ plumbing systems.
Residents of the neighborhood can drink tap water, shower and use air conditioning, the health department said.
How long will it take to identify the source of the outbreak?
There are 179 cooling towers in the affected ZIP codes, according to a Gothamist analysis of city data.
The city health department is in the process of testing all cooling towers in the area for Legionella and is ordering building owners to immediately clean and disinfect any towers whose samples come back positive to get rid of the bacteria, Martin said.
Martin said the city began inspecting the towers and sending water samples to labs for testing on July 2, pulling water ecologists and other staff off vacations and away from other duties during the holiday weekend to ramp up capacity.
By Monday, the city had pulled samples from about a third of the towers in the area.
The remaining towers will be tested in the coming days, city officials said.
But identifying the “smoking gun” cooling tower that caused the outbreak could take weeks, if it happens at all, Martin said.
That involves conducting whole-genome sequencing on the Legionella bacteria found in the cooling towers and trying to match the bacteria to samples from patients who have contracted Legionnaires’.
Not all doctors conduct the type of diagnostic tests — pulled from sputum, rather than urine — that can be used to make that match, said Dr.
Andrea Howard, deputy commissioner of disease control at the city health department.
“That ability to match a patient to a cooling tower may take a very, very, very long time and, quite frankly, the real goal is to treat anything that looks like Legionella,” Martin said of the city health department’s priorities.
This story has been updated with new information.