Sierra Vista Hospital & Clinics Data Breach Investigation

Recently, Sierra Vista reported to the Attorney General of Massachusetts that it had experienced a data breach in which sensitive personal identifiable information and protected health information in its care may have been compromised. According to the breach notice, on or around January 29, 2025, Sierra Vista detected unauthorized access to its network.¹ As a result, Sierra Vista launched an investigation to determine the nature of the incident.

Through its investigation, Sierra Vista confirmed that sensitive personal information in its systems may have been accessed and acquired by an unauthorized third party between January 14, 2025, and January 31, 2025. As a result, Sierra Vista began a review of the data to determine what information had been impacted as well as identify the specific individuals affected. On August 13, 2025, Sierra Vista completed this review. While the information impacted varies depending on the individual, the type of information potentially exposed includes:

• Name
• Social Security number
• Health Records

As a result of the breach, Sierra Vista began mailing data breach notification letters to impacted individuals. Based on the breach notice sent to Massachusetts residents, Sierra Vista is providing affected individuals with a list of the specific types of sensitive information impacted and complimentary credit monitoring services. A link to the breach notification letters that Sierra Vista filed with the Attorney General of Massachusetts is below.