Norovirus outbreaks in a hospital setting: the role of infection control.

AIMS: Noroviruses (NV) (until recently known as Norwalk-like viruses) are a common cause of outbreaks of viral gastroenteritis and can result in significant hospital disruption. We report our experience of two outbreaks that occurred in a geriatric rehabilitation hospital and the role of infection control in limiting their spread. METHODS: The outbreaks occurred in two separate rehabilitation wards for older people. A case definition was developed and a register kept to record patient and staff sickness. The NV was identified from faecal specimens by reverse transcriptase polymerase chain reaction. RESULTS: There were 41 cases in the first outbreak, with an attack rate of 57.1% for patients and 41% for staff. The outbreak lasted 14 days and closed the ward for 11 days. During this outbreak one patient died, with gastroenteritis the precipitating event of his final illness. There were 24 cases in the second outbreak, with an attack rate of 56.5% for patients and 18% for staff. The outbreak lasted 16 days with the ward closed for six days. The mean duration of staff sickness was 3.5 days in the second outbreak compared with only 1.2 days in the first outbreak. In both outbreaks infection was contained within a single ward. CONCLUSIONS: NV infections can significantly disrupt hospitals through their rapid spread to patients and staff as well as the associated high attack rate. Early recognition of an outbreak and prompt implementation of infection control measures, staffing restrictions and ward closure can limit the spread of infection.