HHS OCR report ยท 2023
Health Plan of San Mateo data breach
OCR report facts
- Covered entity
- Health Plan of San Mateo
- Entity type
- Health Plan
- State
- California
- Individuals affected
- 4,032
- Submission date
- Jan 18, 2023
- Type of breach
- Hacking/IT Incident
- Location of breached information
- Network Server
- Business associate present
- Yes
- Status
- Archive (closed)
OCR description
The covered entity (CE), Health Plan of San Mateo, reported that a subcontractor of its business associate (BA) experienced a ransomware incident that affected the protected health information (PHI) of 4,032 individuals. The PHI involved included names, dates of birth, health insurance information, diagnoses, and health assessment information. The CE notified HHS, affected individuals, the media, and posted substitute notice on its website. In response to the breach, the CE and BA implemente...
Text as published on the HHS OCR breach portal.
Other reports by Health Plan of San Mateo
| Covered entity | State | Entity type | Individuals | Submitted | Type of breach | Status |
|---|---|---|---|---|---|---|
| Health Plan of San Mateo | CA | Health Plan | 11,894 | Mar 17, 2023 | Hacking/IT Incident | Archive (closed) |
| Health Plan of San Mateo | CA | Health Plan | 694 | Jun 29, 2011 | Unauthorized Access/Disclosure | Archive (closed) |
Frequently asked questions
How many people were affected by the Health Plan of San Mateo data breach?
The report to HHS OCR lists 4,032 individuals affected.
When was it reported to HHS?
It was submitted to HHS OCR on Jan 18, 2023.
What type of breach was it?
The OCR portal lists the type of breach as Hacking/IT Incident, with the breached information located in: Network Server.
Is the investigation still open?
No. The report is in the OCR portal archive, which holds reports where OCR has closed its review.
Is a breach notice letter from Health Plan of San Mateo legitimate?
This site cannot verify letters. Check the sender against the organisation's official website and the HHS OCR breach portal, and avoid calling numbers or clicking links only listed in an unexpected message. See our guide on what to do after a data breach notice.
Source: HHS OCR Breach Portal, OCR export October 2026. Network USA is not affiliated with HHS or Health Plan of San Mateo.