Tracking the NYC Legionnaires' outbreak

July 12, 2026 — For important background on the Legionnaires’ disease outbreak on the Upper East Side of Manhattan, read this.

Data below are from the New York City Department of Health and Mental Hygiene (DOHMH). Prior to the July 11 report, DOHMH was only providing what I interpreted to be current hospitalizations as of the day of the report. On July 11, I reached out to DOHMH to point out the importance of providing an “aggregate hospitalized” number (that provides important context, including the percentage of diagnosed patients hospitalized at any point). Later on July 11, DOHMH provided a daily count that began to include “discharged,” which, when added to the “currently hospitalized” number, provided the aggregate hospitalizations. Note: I have an inquiry in to DOHMH to confirm that “discharged” refers only to patients who were admitted to the hospital and then discharged, not those patients who came to an Emergency Department, got a diagnosis and antibiotics, and were released without hospital admission.

For context of the current aggregate hospitalization percentage, a 2015 Bronx outbreak had an aggregate hospitalization rate of 93 percent; and 2025 Harlem outbreak had an aggregate hospitalization rate of 78 percent.