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HHS OCR report ยท 2023

Health Plan of San Mateo data breach

Health Plan of San Mateo, a health plan in California, reported a breach affecting 11,894 individuals to HHS OCR on Mar 17, 2023.

OCR report facts

Covered entity
Health Plan of San Mateo
Entity type
Health Plan
State
California
Individuals affected
11,894
Submission date
Mar 17, 2023
Type of breach
Hacking/IT Incident
Location of breached information
Email
Business associate present
No
Status
Archive (closed)

OCR description

The covered entity (CE), Health Plan of San Mateo, reported that an employee was the subject of an email phishing scheme that affected the protected health information (PHI) of 11,894 individuals. The PHI involved included names, dates of birth, diagnoses/conditions, medications, and other treatment information. The CE notified HHS, affected individuals, the media, and posted substitute notice on its website. In response to the breach, the CE implemented additional administrative, technical, ...

Text as published on the HHS OCR breach portal.

Other reports by Health Plan of San Mateo

HIPAA breach reports from the HHS OCR Breach Portal
Covered entityStateEntity typeIndividualsSubmittedType of breachStatus
Health Plan of San MateoCAHealth Plan4,032Jan 18, 2023Hacking/IT IncidentArchive (closed)
Health Plan of San MateoCAHealth Plan694Jun 29, 2011Unauthorized Access/DisclosureArchive (closed)

Frequently asked questions

How many people were affected by the Health Plan of San Mateo data breach?

The report to HHS OCR lists 11,894 individuals affected.

When was it reported to HHS?

It was submitted to HHS OCR on Mar 17, 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: Email.

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.