On April 2, 2020, the Field Epidemiology Training Program was asked by a diabetes mellitus center, Facility A, in Al-Ahsa to investigate a confirmed case of COVID-19 in a health care worker. Patients with diabetes are at increased risk for serious complications from COVID-19.

This study seeks to identify any additional cases, the source of infection and mode of transmission, and implement mitigation measures to prevent further transmission. At the time of the investigation, few COVID-19 cases had been identified in the region.

We reviewed medical charts and other available data on cases in the infection control department, the public health department, and the COVID-19 center. We interviewed cases about their health status and possible sources of infection. We analyzed data using descriptive statistics.

All staff (N=50) at Facility A were tested for COVID-19; 2 (4%) tested positive. The first case was a nurse that reported attending a nursing conference in Riyadh several days prior to symptom onset. She was the first recognized case of COVID-19 in Facility A, so we classified her as the index case. We identified 1 more case that reported using shared cupboard clothes, the same coffee machine, and chatting with the index case in a break room without using personal protective equipment. Both cases reported wearing personal protective equipment during patient care. Both cases survived.

We found evidence of person-to-person transmission between cases while socializing at work, and no evidence of transmission from health care workers to patients. We identified potentially risky practices in Facility A, although none were related to patient care. We helped Facility A develop additional policies to reduce the risk of COVID-19 transmission among staff, even when not providing direct patient care. Facility A was closed during the investigation and reopened after applying all prevention measures.