title: Prospective surveillance of hospitalisations associated with varicella-zoster virus infections in children and adolescents.
abstract: Our goal was to determine the epidemiology of severe varicella-zoster virus (VZV) infections in hospitalised paediatric patients. Admissions associated with VZV infection of patients aged 0-16 years were reported by all 38 paediatric units in Switzerland to the Swiss Paediatric Surveillance Unit (SPSU) during 3 consecutive years (4/2000-3/2003). We verified completeness of reporting by capture-recapture analysis with patient records identified by ICD-10 codes. Outcome of illness was assessed 6 months after hospitalisation. A total of 335 cases (235 identified by SPSU reports, 100 by ICD-10 code) were included in this study. Mean age of patients was 4.1 years (median 3.5 years, range 0-16 years); 54% were male. Some 293 (87%) patients presented with chickenpox, 42 (13%) with herpes zoster and 291 (87%) patients were not immunocompromised. A total of 319 complications occurred in 237 (71%) patients: secondary bacterial infections (n =109); central nervous system involvement (n =76); VZV pneumonitis (n =7); others (n =127). Eleven (3%) patients required intensive care and three died. On follow-up, 303 (96%) of 315 patients had completely recovered; sequelae were present in 12 (4%) patients. The calculated hospitalisation rate was 13 per 10(4) cases.
  
  
  CONCLUSIONS
  This study describes a sizeable hospitalisation and complication rate of varicella-zoster virus infections and provides a solid basis for future immunisation recommendations in Switzerland.
authors.affiliation: Division of Paediatric Infectious Diseases, University Children's Hospital, P.O. Box, 4005, Basel, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Bonhoeffer
authors.forename: Gurli
authors.initials: G
authors.lastname: Baer
authors.forename: Beda
authors.initials: B
authors.lastname: Muehleisen
authors.forename: Christoph
authors.initials: C
authors.lastname: Aebi
authors.forename: David
authors.initials: D
authors.lastname: Nadal
authors.forename: Urs B
authors.initials: UB
authors.lastname: Schaad
authors.forename: Ulrich
authors.initials: U
authors.lastname: Heininger
mesh_terms: D000293:Adolescent; D002644:Chickenpox / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D005260:Female; D006562:Herpes Zoster / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D016867:Immunocompromised Host; D007223:Infant; D007231:Infant, Newborn; D016013:Likelihood Functions; D008297:Male; D011446:Prospective Studies; D016036:Seroepidemiologic Studies; D013557:Switzerland / Q000453:epidemiology