A cluster of Legionnaires' disease on Manhattan's Upper East Side has continued to grow, with New York City health officials now reporting 63 confirmed cases and no deaths so far reported, even as the pace of new infections has slowed. The affected neighborhoods span Carnegie Hill, Yorkville and Lenox Hill, and authorities are urging residents, workers and visitors with symptoms to seek medical care while the investigation into the source continues.
A separate positive test on the other side of Manhattan briefly raised concern but has been played down by officials. According to health officials, Legionella was found in the hot water system of a building at 320 Central Park West on the Upper West Side, between 91st and 92nd Streets, but they say it is not related to the Upper East Side outbreak and that there are no confirmed cases on the Upper West Side. Officials said the building's owner had tested the hot water system independently, without first consulting the health department, something they noted owners sometimes do during a high-profile community cluster.
In response to mounting questions from the community, the city's Health Department has scheduled a virtual town hall for Wednesday at 6 p.m. Officials plan to use the session to update residents on the outbreak and address their concerns, as anxiety builds in a part of Manhattan that is home to many older residents who are especially vulnerable to the illness.
The city has taken concrete steps against the suspected sources. Thirty-one buildings that tested positive for Legionella bacteria have been ordered to disinfect their cooling towers, and officials have publicly identified them for the first time. The list includes the Guggenheim museum, a 20-story co-op near Gracie Mansion and a Whole Foods on Third Avenue, while a building at 1511 Third Avenue was issued a remediation order after testing positive. Officials said the buildings were ordered to clean and disinfect their cooling towers immediately, and that as of Friday 19 of the 31 had completed the process, with the remaining 12 directed to finish over the weekend.
Health officials believe the likely source of the outbreak is a cooling tower in the area that sprays a mist containing Legionella. They have stressed that this is not a problem with any building's plumbing system, meaning residents in the affected zip codes can continue to drink tap water and to bathe, shower, cook and run their home air conditioning as normal.
The illness itself is a form of pneumonia. Legionnaires' disease is caused by breathing in water vapor that contains Legionella bacteria, and doctors emphasize that it is not spread from person to person. It is not contracted from home air conditioning units or from drinking tap water, and it is typically diagnosed through a urine test and treated with antibiotics.
Officials have issued clear guidance for the public. Anyone who lives or works in the affected area, or who has recently spent time there, and is experiencing flu-like symptoms such as fever, cough or difficulty breathing has been advised to contact a healthcare provider right away, since early treatment improves the odds of a full recovery.
The response has unfolded against a sobering backdrop. A similar Legionnaires' outbreak in Harlem last year killed seven people and sent more than 100 others to the hospital, a memory that has sharpened residents' fears this time. The Upper East Side has roughly 160 cooling towers, which the city routinely tests each month during the warmer season in an effort to head off outbreaks.
Local officials have pushed the Health Department to move faster. City Council member Julie Menin, who represents the affected neighborhoods, has urged that any building still awaiting test results disinfect its cooling towers in the meantime rather than wait, arguing that officials should be aggressive while the exact source of the cluster has yet to be confirmed.
In a later update, health officials pointed to signs that the outbreak was beginning to ease. According to the account, just over half of the people who had been hospitalized for Legionnaires' disease as part of the cluster had made it through the process and been discharged, a number officials put at 33. They said the pattern of new cases showed a large cluster of diagnoses between July 1 and July 8 before tapering off, with some days recording no new cases, and noted that the incubation period for the disease runs between two and 10 days, sometimes as long as 14.
By the twelfth day of the investigation, the health commissioner reported that the numbers were trending in the right direction and that the cluster had entered a new phase. New cases had slowed significantly, with just one new case identified the previous day, and officials said there had still been no deaths, while more than half of all the patients who had been hospitalized had since returned home.
The city said it had also finished sampling the suspected sources. All 183 cooling towers flagged as a potential source of the bacteria had been tested, and every building that came back positive, a total of 76 on the Upper East Side, had been ordered to disinfect, with 57 having completed the cleaning and the rest given until Thursday to finish. Officials said it remained unclear whether the towers that tested positive held live bacteria, as those results were still pending. Council member Lynn Schulman, meanwhile, tied the department's earlier struggles to a lack of resources, pointing to a law requiring buildings to test their cooling towers every 31 days during the summer that she said had gone unenforced even as officials concentrated on the current outbreak.