Kokikai Yasue Hospital

Kokikai Yasue Hospital is a medical institution located in Japan that provides a range of healthcare services, including inpatient and outpatient care, diagnostic examinations, treatment procedures, and preventive health services. The hospital maintains electronic health records that contain personal identifiers, medical histories, treatment details, and immunization information, including COVID‑19 vaccination histories. The breach report noted that the exposed patient data included names, dates of birth, contact details, medical histories, treatment specifics, and COVID‑19 vaccination histories. According to a publicly reported data breach affecting the hospital, the personal and medical data of approximately 111,191 patients and 715 employees were potentially exposed, indicating the scale of its patient base and workforce. This figure reflects the volume of individuals whose information is routinely managed within the hospital’s information systems.

The presence of COVID‑19 vaccination histories in its records indicates that the hospital provides vaccination services as part of its preventive care offerings. The institution’s reliance on digital record‑keeping systems places it within the broader trend of healthcare providers adopting electronic medical records to improve care coordination and clinical decision‑making. While the specific ownership structure or any parent‑subsidiary relationships are not disclosed in the available sources, the hospital operates under Japan’s healthcare regulatory framework, which governs patient safety, data protection, and medical service standards. The July 2022 incident, which involved unauthorized access to its internal computer systems and was suspected to involve ransomware, highlights the cybersecurity challenges faced by healthcare organizations that manage large volumes of personal health information. The event resulted in a significant data leakage but did not reveal details about operational disruption or the identity of the threat actor.