To describe a nosocomial norovirus outbreak, its management, and its financial impact on hospital resources.

A matched case-control study and microbiological investigation.

We compared 16 patients with norovirus infection with control-patients matched by age, gender, disease category, and length of stay. Bed occupancy-days during the peak incidence period of the outbreak were compared with the corresponding periods in 2001 and 2002. Expenses due to increased workload were calculated based on a measuring system that records time spent for nursing care per patient per day.

The attack rates were 13.9% among patients and 29.5% among healthcare workers. The median number of occupied beds was significantly lower due to bed closure during the peak incidence in 2003 (29) compared with the median number of occupied beds in 2001 and 2002 combined (42.5). Based on this difference and a daily charge of $562.50 per patient, we calculated a revenue loss of S37.968. Additional expenses totaled $10,300 for increased nursing care. Extra costs for microbiological diagnosis totaled $2,707. Lost productivity costs due to healthcare workers on sick leave totaled $12,807. The expenses for work by the infection control team totaled $1,408. The financial impact of this outbreak on hospital resources comprising loss of revenue and extra costs for microbiological diagnosis but without lost productivity costs, increased nursing care, and expenses for the infection control team totaled $40,675.

Nosocomial norovirus outbreaks result in significant loss of revenue and increased use of resources. Bed closures had a greater impact on hospital resources than increased need for nursing care.