- State
- IL
- Covered entity type
- Healthcare Provider
- Individuals affected
- 1,248,546
- Business associate present
- Yes
- Type of breach
- Hacking/IT Incident
- Location of breached information
- Network Server
- First seen by InfoSec Signals
- 9/23/2026
- Last seen in OCR export
- 9/23/2026
OCR description
Cook County Health and Hospitals System, the covered entity (CE), reported that its business associate (BA) experienced a ransomware attack that compromised the protected health information (PHI) of 1,248,546 individuals. The PHI involved included names, addresses, dates of birth, Social Security numbers, diagnoses, and other treatment information. The CE notified HHS, affected individuals, and the media. In response to the breach, the CE terminated its business relationship with the BA.
Change history
- 9/23/2026Added to OCR's archive list
Source: U.S. Department of Health and Human Services, Office for Civil Rights, Breach Portal. Records are reproduced as published; entity names and figures are OCR's.