A growing cluster of Legionnaires' disease cases on Manhattan's Upper East Side has reached 63 confirmed infections, including more than two dozen hospitalizations, according to city health officials.

The New York City Health Department said 12 people were hospitalized as of Monday, with 40 people discharged and 11 not hospitalized. No deaths have been reported.

Mayor Zohran Mamdani said Friday that every cooling tower that tested positive for Legionella bacteria has now been disinfected.

Investigators have identified 31 cooling towers that tested positive for the bacteria within the outbreak area, which spans three Upper East Side ZIP codes.

Officials cautioned that a positive test does not necessarily mean a building is the source of people's infections, and said confirming the exact source of the outbreak could still take weeks.

The following buildings have cooling towers that have tested positive for Legionella bacteria:

• 1750 York Ave.
• 180 East End Ave.
• 1660 2nd Ave.
• 1438 3rd Ave.
• 1511 3rd Ave.
• 1551 3rd Ave.
• 1071 5th Ave.
• 1080 5th Ave.
• 1001 5th Ave.
• 240 E 82nd St.
• 8 E 83rd St.
• 145 E 84th St.
• 117 E 85th St.
• 125 E 87th St.
• 152 E 87th St.
• 120 E 87th St.
• 501 E 87th St.
• 168 E 88th St.
• 160 E 88th St.
• 1875 2nd Ave.
• 1110 5th Ave.
• 153 E 78th St.
• 135 E 79th St.
• 300 E 79th St.
• 238 E 81st St.
• 160 E 84th St.
• 114 E 85th St.
• 401 E 88th St.
• 333 E 91st St.
• 354 E 91st St.
• 312 E 95th St.

Officials said people who live, work or have visited those areas since late June should monitor for symptoms and seek medical care if they become ill.

Legionnaires’ disease is a type of pneumonia caused by Legionella bacteria that thrive in warm water. Symptoms include cough, fever, muscle aches and difficulty breathing.

The Health Department said that the investigation is not related to any building's plumbing system. Residents can continue to safely drink tap water, bathe, shower, cook and use air conditioning in their homes.

The disease is not contagious and cannot be spread from person to person.

Those at greatest risk include adults age 50 and older, people who smoke or vape, those with chronic lung disease, weakened immune systems or people taking medications that suppress the immune system, according to the department.

The agency believes the source of the bacteria is likely a cooling tower in the affected area. It is testing cooling towers throughout the affected area.

The cluster follows a Legionnaires' disease outbreak in Central Harlem last summer that sickened more than 100 people and killed seven.