A norovirus outbreak among healthcare workers

BACKGROUND: Noroviruses have accounted for numerous outbreaks in communities, long-term care facilities, and hospitals. On February 20, 2004, employee health services (EHS) reported 6 cases of gastroenteritis (GE) among hospital staff members. The infection control department initiated an outbreak investigation. METHODS: A case of GE was defined as a person with two or more episodes of diarrhea and/or vomiting in a 24 hour period. Cultures (5 viral, 3 bacterial) were collected and sent to the Maryland Department of Health and Mental Hygiene for testing. Case finding included a questionnaire administered to employees presenting to EHS with GE symptoms and reports from managers of employees reporting GE illness. Visitors with GE symptoms were restricted from the hospital and no children under age 12 were permitted to visit during the outbreak. Staff members with GE were restricted until 72 hours after symptoms had resolved. Hand hygiene was reinforced. Inservices were conducted. Letters and e-mails were sent to all staff notifying them of the outbreak and instructing them what to do if they experienced symptoms. Signs were posted throughout the hospital notifying staff and visitors of an outbreak. One unit was closed for 8 days due to the number of staff affected. RESULTS: Between February 10 and March 24, 2004, 316 staff (8% of hospital staff), including the only EHS employee, met the case definition. No patients qualified as cases. There were 74 (23%) staff members affected on two units. Three of five specimens submitted for viral testing were positive for norovirus. No bacterial cultures were positive. The outbreak was declared over 30 days after control measures were implemented. CONCLUSIONS: A norovirus outbreak occurred between February and March 2004. Norovirus among hospital staff is difficult to prevent and control when control measures are not strictly and consistently enforced. Areas for improvement for preventing and shortening the duration of future outbreaks include: enforcement of the visitor policy; having ill staff sent more quickly to EHS for evaluation; developing a contingency plan for limited staffing in EHS; consistently enforcing staff restriction from work; and consider providing time off for affected staff during an outbreak. As a result of this outbreak, an outbreak policy was developed. This outbreak highlights the importance of consistent communication and enforcement of policies at all levels of the organization.