J. Paediatr. Child Health (2004) 40, 449–454 Evolution of an adenovirus outbreak in a multidisciplinary children’s hospital M Hatherill, 1 M Levin, 2 J Lawrenson, 3 N-Y Hsiao, 4 L Reynolds 1 and A Argent 1 1 Paediatric Intensive Care Unit, 2 Allergy Service and 3 Cardiology Service, Red Cross Children’s Hospital, and 4 Virology Laboratory, University of Cape Town, Cape Town, South Africa Objective: To describe the course of an evolving adenovirus outbreak in a multidisciplinary children’s hospital with a high-risk patient population. Methods: Observational study in a 280-bed university hospital during June 2002. Active case finding identified children with adenovirus infection. Data are median (interquartile range) or n (%). Adenovirus infection was diagnosed in 49 children, median age 12 months (4–33). Results: New cases were diagnosed over 26 days and peaked on day 17 ( n = 15). Total infected inpatients peaked on days 17–21 (n = 36). Twenty-three infections (47%) were community-acquired and 26 (53%) hospital-acquired. Thirty-three children (67%) had a coexistent high-risk condition. Median hospital stay before and after diagnosis was 9 days (3–18) and 9 days (4–29), respectively. Twenty-two children (45%) were admitted to PICU. Overall hospital mortality was 22% ( n = 11) and mortality attributed to adenoviral disease 12% ( n = 6). Hospital mortality was similar between community- and hospital- acquired infections (22% compared to 23%) ( P = 1.0). Twenty children (41%) received intravenous immunoglobulin (IVIG). Children treated with IVIG had a longer hospital stay (median 40 days vs 14 days) than those who did not receive IVIG ( P = 0.01). Neither PICU mortality (29% vs 12%), nor hospital mortality (35% vs 14%), differed significantly between IVIG treated and untreated children ( P = 0.76 and P = 0.16, respectively). Conclusion: The rapid spread of hospital-acquired adenovirus underlines the importance of effective infection control measures. Despite nosocomial infection amongst high-risk patients, mortality was similar to that of community-acquired infection. Administration of immunoglobulin was not associated with demonstrable benefit. A prospective randomized trial would be required to resolve this issue. Key words: adenovirus; child; hospital; nosocomial; outbreak. Adenovirus is responsible for 4–6% of lower respiratory tract infections in children in some regions. 1,2 Reports of long-term surveillance in South-east Asia describe sporadic cases of adenovirus infection occurring throughout the year, with serotypes 3 and 7 causing localized epidemics. 1 Elsewhere, Mitchell has described a large outbreak of adenovirus in the south-eastern United States, in which 92% of infections were community-acquired, with 4% mortality. 3 In other regions, such as South America, adenovirus is particularly common amongst children hospitalized for lower respiratory tract infec- tions, and secondary attack rates of 55%, with 11% mortality, have been reported. 4 Adenovirus has also been responsible for outbreaks of hospital-acquired respiratory infection in high-risk children resident in chronic care facilities, and the mortality among such children, who often have coexistent respiratory disease, has ranged from 20% to 39%. 5–7 In southern Africa, Wesley has described a nosocomial outbreak of adenoviral infection in a paediatric respiratory unit with a massive 91% mortality for hospital-acquired infection, and 67% mortality overall. 8 This report describes the evolution of a nosocomial out- break, the clinical course and outcome of infected patients, infection control measures, and the impact on tertiary hospital services such as intensive care, in a multidisciplinary paediatric referral hospital in Cape Town, South Africa. METHODS We report an observational study of an evolving adenovirus outbreak in the general paediatric and subspeciality wards, and paediatric intensive care unit (PICU), of a 280-bed university children’s hospital. All children admitted to the Red Cross Children’s Hospital in whom adenovirus was diagnosed were prospectively identified, by means of active case finding, from the start of the outbreak until no further new cases were diagnosed. Thereafter the records of the Virology Laboratory of the University of Cape Town were retrospectively reviewed to identify cases that had gone undetected. Clinical records were reviewed and the following data were collected: age; primary diagnosis; coexistent high-risk con- ditions including premature birth, congenital cardiac disease, tracheostomy, or immunosuppression, whether due to human immunodeficiency virus (HIV) infection, recent oncotherapy, or organ transplantation; community or nosocomial acquisition of adenovirus infection; ward admissions and in-hospital contact with infected patients; duration of symptoms prior to diagnosis; symptoms including: asymptomatic, conjunctivitis, upper respiratory tract infection (URTI), pneumonia, or dis- seminated disease; duration of hospital stay prior to, and after, diagnosis of adenovirus infection; admission to PICU; duration of PICU stay; assisted ventilation; duration of ventilation; Correspondence: Dr Mark Hatherill, Institute of Child Health, Red Cross Children’s Hospital, Klipfontein Road, Cape Town 7700, South Africa. Fax: + 27 21 689 1287; email: hatheril@ich.uct.ac.za Accepted for publication 15 January 2004. MH, ML and JL conceived the study. MH and ML collated data, and MH wrote the manuscript. N-YH contributed data, and N-YH, JL, LR, and AA edited the manuscript.