New York City health officials are investigating a growing number of Legionnaires disease cases on the Upper East Side, and the warning is aimed at a specific part of Manhattan.
The latest NYC Health Department update lists 18 cases in Carnegie Hill and Yorkville. The affected ZIP codes are 10028, 10128, and 10075. No deaths have been reported in the current investigation.
Health officials are telling people who live, work, or spend time in the area since late June to watch for symptoms. The main warning signs are fever, cough, chills, muscle aches, and trouble breathing.
The message is not that every New Yorker should panic. The message is more specific. People in the affected area should know the symptoms, and higher-risk residents should call a doctor quickly if they start to feel sick.
The city investigation is focused on Carnegie Hill and Yorkville on the Upper East Side. The affected ZIP codes are 10028, 10128, and 10075.
The city is looking for an environmental source. In cases like this, investigators often test cooling towers and other water systems that can release mist into the outdoor air.
What is Legionnaires Disease?
Legionnaires disease is a serious type of pneumonia. It is caused by Legionella bacteria.
The bacteria can grow in warm water systems. People can get sick when they breathe in tiny water droplets, or mist, that contain Legionella. That mist can come from cooling towers, hot tubs, spray fountains, decorative fountains, or large building water systems when they are not properly maintained.
The disease is not spread from person to person. A person does not get it by sitting next to someone who is sick, walking past them, or touching the same surface.
The CDC says symptoms usually develop 2 to 14 days after exposure. They can look like other lung infections at first, which is why people may not know right away that they need a specific test.
Symptoms People Should Watch For
People who were in the affected Upper East Side area since late June should pay attention to symptoms that feel like flu or pneumonia.
| Symptom | Why it matters |
| Fever | Can be an early sign of infection. |
| Cough | Can point to pneumonia when paired with fever or weakness. |
| Chills | Can appear with a serious bacterial infection. |
| Muscle aches | Can make the illness feel like flu at first. |
| Shortness of breath | Should be treated seriously, especially in older adults or people with lung disease. |
| Confusion, diarrhea, or nausea | Can appear in some Legionnaires disease cases. |
Breathing trouble should not be ignored. Readers can also review our guide to symptoms that often lead people to the ER, because shortness of breath is one of the warning signs that needs fast attention.
Most healthy people exposed to Legionella do not get sick. The risk is higher for certain groups.
- Adults age 50 and older
- People who smoke or vape
- People with chronic lung disease
- People with weakened immune systems
- People taking medicines that weaken the immune system
- People with serious health problems such as cancer, kidney disease, diabetes, or long-term lung illness
Older adults should be especially careful because pneumonia can worsen faster when other medical problems are already present. Our reporting on chronic disease among older adults explains why infections can be more dangerous for people already managing long-term health conditions.
People with asthma, COPD, or other breathing problems should also take symptoms seriously. Our article on asthma and respiratory hospitalizations shows how quickly breathing problems can become urgent when the lungs are already under stress.
Why Are Cooling Towers Important?
View this post on Instagram
Cooling towers are used by large buildings to remove heat from air conditioning and mechanical systems. They contain water. If the water is not maintained properly, Legionella can grow.
If contaminated mist leaves the tower, people nearby can breathe it in. That is why a health investigation can focus on buildings even when the people who got sick do not all live in the same building.
New York City requires building owners to register cooling towers and maintain them. Residents can look up cooling tower registration information by building or address.
If testing finds Legionella in a cooling tower, the building owner can be ordered to clean and disinfect the system.
When to Call a Doctor?
People who were in Carnegie Hill, Yorkville, or the affected ZIP codes since late June should call a healthcare provider if they develop fever, cough, chills, muscle aches, or breathing problems.
Higher-risk people should not wait to see if symptoms pass. That includes adults over 50, smokers, people with lung disease, and people with weakened immune systems.
A doctor may order a chest X-ray and a lab test for Legionella. Patients should tell the doctor they recently spent time on the Upper East Side, where the city is investigating cases. That detail can help the provider choose the right test sooner.
People should not take antibiotics only because they walked through the area. Treatment is for people who are sick and need medical evaluation.
Should New Yorkers Be Worried?
#Legionnaires‘ disease is a serious type of #pneumonia caused by the bacterium Legionella pneumophila. People contract the disease by breathing in fine water droplets containing #Legionella.
🔗 https://t.co/noOChEBLtz pic.twitter.com/eKbdcceHxb
— UK Health Security Agency (@UKHSA) March 12, 2026
People should be alert, not frightened.
The cases are serious because Legionnaires disease is pneumonia and can become dangerous. The risk is higher for older adults, smokers, and people with lung or immune system problems.
The wider public should also keep the facts in view. The disease is not spread from one person to another. No deaths have been reported in the current Upper East Side investigation. City officials say normal tap water use, showering, cooking, and home air conditioning remain safe.
New York has dealt with bacterial public health threats before, and the lesson is usually the same. Fast testing, early treatment, and finding the source matter. Our reporting on dangerous bacterial infections explains why delays can make bacterial illnesses harder to manage.
Bottom Line
@abcnewsA fifth person has died in connection with a Legionnaires’ disease outbreak in New York City, health officials said. The outbreak in Central Harlem has sickened dozens since it began in late July and the latest death was announced late Monday night.♬ original sound – ABC News
New York health officials are investigating Legionnaires disease cases on the Upper East Side, with the warning focused on Carnegie Hill and Yorkville.
People who were in ZIP codes 10028, 10128, or 10075 since late June should watch for fever, cough, chills, muscle aches, and trouble breathing. Higher-risk residents should seek medical care quickly if symptoms appear.
People without symptoms do not need treatment just because they were in the area. The practical response is to know the symptoms, take breathing problems seriously, and follow updates from city health officials as testing continues.
