title: Prospective surveillance of hospitalisations associated with varicella in New Zealand children.
abstract: OBJECTIVE
  Varicella is a vaccine-preventable disease not notifiable in New Zealand (NZ), and varicella vaccine is not funded in the National Immunisation Schedule (NIS). Hospitalisations can occur because of bacterial secondary infection and other complications, which can result in long-term sequelae. Varicella may not be acknowledged in discharge coding when complications occur weeks after infection. Using the New Zealand Paediatric Surveillance Unit (NZPSU), the aim of this study was to document the hospitalisation burden of this disease.
  
  
  METHODS
  Cases (0-14 years) of varicella and post-varicella complications requiring hospitalisation, including stroke syndromes where varicella occurred in the preceding 6 months, were notified to NZPSU between 1 November 2011 and 31 October 2013. Herpes zoster cases were excluded. Questionnaires were used to capture demographics, clinical features, management and short-term outcomes.
  
  
  RESULTS
  One hundred seventy-eight notifications were received and 144 were confirmed cases. Overall incidence was 8.3/100,000 children per year. Fifty-two percent were women with a median age of 2.4 years. Māori and Pacific Island (PI) children accounted for 74% of hospitalisations, with incidence rate ratios compared with European children of 2.8 and 3.9, respectively (P < 0.01). Complications included: infection (75%), respiratory (11%), neurological (11%), electrolyte disturbance (6%) and haemorrhagic varicella (4%). Nine percent were immunocompromised. Median duration of hospital admission was 4 days with 9% requiring intensive care admission. There were no reported deaths; however, 19% had ongoing problems at discharge.
  
  
  CONCLUSIONS
  Varicella has more associated morbidity than commonly perceived in immunocompetent children. Māori and PI children are more likely to have complications. This surveillance gives support for inclusion of universal varicella vaccine in the NZ NIS.
authors.affiliation: Departments of Paediatric Infectious Diseases, Starship Children's Hospital, Auckland, New Zealand.
authors.forename: Sophie Chien-Hui
authors.initials: SC
authors.lastname: Wen
authors.affiliation: Departments of Paediatric Infectious Diseases, Starship Children's Hospital, Auckland, New Zealand.|Department of Paediatrics, University of Auckland, Auckland, New Zealand.
authors.forename: Emma
authors.initials: E
authors.lastname: Best
authors.affiliation: Department of Paediatrics, University of Otago, Christchurch, New Zealand.
authors.forename: Tony
authors.initials: T
authors.lastname: Walls
authors.affiliation: New Zealand Paediatric Surveillance Unit, Department of Women's and Children Health, University of Otago, Dunedin, New Zealand.
authors.forename: Nigel
authors.initials: N
authors.lastname: Dickson
authors.affiliation: Department of Paediatrics, University of Auckland, Auckland, New Zealand.|Department of Paediatrics, Waikato Hospital, Waikato, Hamilton, New Zealand.
authors.forename: Hamish
authors.initials: H
authors.lastname: McCay
authors.affiliation: Departments of Paediatric Infectious Diseases, Starship Children's Hospital, Auckland, New Zealand.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Wilson
mesh_terms: D000293:Adolescent; D002644:Chickenpox / Q000453:epidemiology* / Q000517:prevention & control; D019433:Chickenpox Vaccine / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D011159:Population Surveillance; D011446:Prospective Studies; D011795:Surveys and Questionnaires
chemical_list: D019433:Chickenpox Vaccine
keywords: immunisation; infectious disease; varicella