1. NOROVIRUS OUTBREAK IN A UNIVERSITY TEACHING HOSPITAL O Meara M, O Connor M, Dept of Public Health, Dr. Steevens Hospital Background On March 7th 2006, the Department of Public Health received telephone notification of an outbreak of gastrointestinal illness in patients and staff in a Dublin teaching hospital. Norovirus had been confirmed in 5 stool samples sent to the National Virus Reference Laboratory. Infection control measures were instigated 1,2. An outbreak control team had been convened The Department of Public Health received 6 notification of norovirus infection from the catchment area (Population 365,000) in the 4 weeks prior to the outbreak suggesting low background community levels The hospital is a tertiary referral centre with approximately 500 acute beds and 2,000 staff members of whom 65% are frontline staff (medical, nursing and paramedical). Key points Lack of laboratory facilities for environmental sampling Lack of capacity in Dept of Public Health Hospital Issues (see below) Hospital Issues Patients High Occupancy rates contribute to spread In acute hospital setting all procedures considered necessary therefore staff and patient movement difficult to curtail Elderly, Ill and Population in closed/semi closed communities at particular risk. Competing priorities: No smoking Policy vs. isolating infected patients who smoke Occupational Health All staff including medical staff to report illness. Gathering of enhanced information early in outbreak essential Communication E-Mail/Memo may not be most effective means of communication in a hospital outbreak setting Posters and Leaflets available in advance of outbreak Appropriate representation required at OCT including senior consultant staff and representative of student groups (medical, nursing, paramedical) Staff Increase awareness and implementation of infection control policies Role of Heads of Discipline in re-organising work plans for staff working in several locations Availability of fresh uniforms for staff after their uniforms are contaminated environmentally. Cleaning Availability of additional cleaning staff. When to institute norovirus cleaning guidelines eg await lab confirmation or when projectile vomiting. Where Early instigation of hypochlorite in A&E setting to prevent seeding in ward setting Ward level where two or more clinical cases Hospital setting- confirmed cases/hospital outbreak- cases in any location Staff Questionnaire Administered to first 40 reporting symptomatic staff members, 24 of whom were frontline staff. Response rate 16/40 (40%). Diverse occupational categories represented Staff working in multiple locations possibly contributed to spread (Person to person and environmental contamination). Some staff members worked whilst sick A&E possible source of initial spread, with subsequent spread within and between wards. Role of patient movement staff movement, environmental contamination (vomit) & occupancy rates in spread of infection. Epidemiology 1 Peak onset 7th- 9th March- Point Source and Person to Person spread Patient profile determined by date of onset of symptoms. Staff profile determined by date reporting to occupational health-staff date of onset likely to be 24-38 hours earlier. 5 A&E Patients who spent an average of 32 hours in A&E (range 10-55 hours) during the period 2nd-4th March were subsequently admitted to 3 different wards and were later identified as a possible source of infection on these wards (See Epidemiology 2). Total Number of staff affected =200- of whom 107 (53.5%) were frontline staff. Total number of patients affected=226. Diarrhoea was the predominant symptom in patients and staff with 171(75.6%) of affected patients and 90 (45%) of affected staff members having diarrhoea. 108 (47.7%) of affected patients and 78 (39%) of affected staff members had a history of vomiting. Age and Sex Profile of Affected Patients (N=178) Microbiological results Laboratory Notifications from NVRL to Dept. of Public Health confirmed 5 patients (not admitted) attended A&E over period 1st-6th March had stool samples confirming Norovirus. Environmental No facilities currently available in Ireland for checking food and water samples for viral studies Epidemiology 2 Patients admitted from A&E for reasons other than Gastroenteritis, subsequently developed Norovirus infection. Their stay overlapped in A&E with symptomatic non-admitted patients (see Microbiological above). Those admitted subsequently became sources of infection on individual wards. Person to Person spread was a factor. Hospital Patient tracking system allowed analysis at ward level Each ward could be considered as different OB as different factors in play Ward A Epidemic Curve presented below as representation of pattern of spread in wards. Patient admitted from A&E* Age groupFemaleMaleTotal% 15-441181910.6 45-6423184123.2 65-7418193720.7 75-8424234726.4 85+21133419.1 Numbers% Onset of symptoms prior to admission31.8 Onset on Day of admission84.6 Onset within 48 hours after admission2213.4 Onset 48 hours-10 days post admission8250.1 Onset 10+ days5820.1 Length of Stay prior to symptom onset (N=163) Acknowledgements. Members of OCT Team, Corporate Affairs Environmental Health Officers, NVRL This data outlines that for the majority of patients infection was nosocomically acquired. *Patient spent 22 hours in casualty prior to admission References 1. National Disease Surveillance Centre.2003 National Guidelines in the Management of Norovirus infection ion the Healthcare Setting 2. Chadwick et Al Management of hospital outbreaks of gastro-enteritis due to small round structured virus J of Hospital infection 2000 45: 1-10