P01 SEVERE COMPLICATIONS OF CHICKENPOX IN HOSPITALISED CHILDREN

J. C. Cameron¹, G. Allan¹, F. Johnston¹, R. Booy², P. T. Heath³, A. Finn⁴.¹Health Protection Scotland, Glasgow, UK; ²Royal London Hospital, London, UK; ³Institue of Child Health, Bristol, UK; ⁴St Georges Hospital, London, UK

Introduction: Varicella (chickenpox) is generally a mild disease, but severe complications can occur even in previously healthy children. There are few data on complicated varicella in the UK and further information could help determine immunisation policy, either for specific risk groups, or as a universal programme.

Aims: To estimate the annual incidence of severe complications of varicella in hospitalised children, to describe the complications and affected children, to estimate annual mortality, and to provide economic data.

Methods: Active surveillance was carried out throughout the UK and Ireland during the period November 2002 to November 2003, through the British Paediatric Surveillance Unit. Paediatricians were prompted monthly to notify cases meeting the definition below and a questionnaire was sent requesting further clinical and epidemiological data.

Case Definition: Any child aged <16 years hospitalised with complicated varicella, as defined by list of clinical conditions (bacteraemia/septic shock, toxic shock syndrome/toxin-mediated disease; necrotising fasciitis; encephalitis; purpura fulminans/disseminated coagulopathy; pneumonia (abnormal x ray); neonatal varicella; fulminant varicella; Reye’s syndrome; ataxia; death due to varicella), or admitted to a paediatric ICU or HDU with varicella or one of its complications.

Results: Over the 13 month period, 188 cases were notified: 118 (63%; 0.86/100 000 children per year) met the case definition, 22 (12%) duplicates, 28 (15%) did not meet the case definition, 6 (3%) errors, 14 (7%) lost to follow up. Confirmed cases had a median age of 3 years (range 0–14). The most frequent complications stated were bacteraemia/septic shock (n = 34), pneumonia (n = 31), encephalitis (n = 27), and …