title: Invasive group A streptococcal disease in children and association with varicella-zoster virus infection. Ontario Group A Streptococcal Study Group.
abstract: OBJECTIVE
  To describe the incidence and clinical features of invasive group A streptococcal (GAS) disease in children in Ontario and determine the risk of invasive GAS infection following chickenpox.
  
  
  METHODS
  During 1992-1996, we conducted prospective, active, population-based surveillance for pediatric invasive GAS disease in Ontario, Canada (population: 11 million; 2.5 million children) and reviewed clinical and laboratory records.
  
  
  RESULTS
  There were 1.9 cases of invasive GAS disease per 100,000 children per year. Streptococcal toxic shock syndrome (STSS) occurred in 7% of cases and necrotizing fasciitis (NF) in 4% for incidences of.08 and.13 per 100,000 per year, respectively. Case-fatality rates were 56% for STSS, 10% for NF, and 4% overall. The presence of chronic underlying illness other than asthma was associated with death (relative risk [RR]: 11; 95% confidence interval [CI]: 2.4-45). Fifteen percent of children identified had preceding chickenpox infection, which significantly increased the risk for acquisition of invasive GAS disease (RR: 58; 95% CI: 40-85). Children with invasive GAS and recent chickenpox were more likely to have NF (RR: 6.3; 95% CI: 1.8-22.3).
  
  
  CONCLUSIONS
  Childhood invasive GAS disease occurs at an incidence similar to the adult population but has a lower rate of STSS and case-fatality. Chickenpox dramatically increases the risk for acquiring invasive GAS disease, and universal chickenpox vaccination could potentially prevent up to 15% of all pediatric invasive GAS disease.
authors.affiliation: Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.
authors.forename: K B
authors.initials: KB
authors.lastname: Laupland
authors.forename: H D
authors.initials: HD
authors.lastname: Davies
authors.forename: D E
authors.initials: DE
authors.lastname: Low
authors.forename: B
authors.initials: B
authors.lastname: Schwartz
authors.forename: K
authors.initials: K
authors.lastname: Green
authors.forename: A
authors.initials: A
authors.lastname: McGeer
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002644:Chickenpox / Q000150:complications* / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D009864:Ontario / Q000453:epidemiology; D016012:Poisson Distribution; D011159:Population Surveillance; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D013290:Streptococcal Infections / Q000150:complications* / Q000453:epidemiology* / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000145:classification