Varicella zoster virus infections in Canadian children in the prevaccine era: A hospital-based study

Abstract

OBJECTIVE: To describe the clinical course of children admitted for varicella zoster virus (VZV) infections to a pediatric hospital before the release of VZV vaccine in Canada. DESIGN: Retrospective case series. SETTING: Tertiary pediatric hospital. Population studied was children aged 18 years or younger admitted to hospital between 1983 and 1992 who were discharged with a diagnosis of varicella or zoster. Of the 201 children who were identified, 36 were excluded, leaving 165 for analysis. RESULTS: There was a male:female ratio of 1.5:1 and a median age of 5.3 years (range two weeks to 18 years). The group included those who were previously healthy (70, 42.4%), immunocompromised (60, 36.4%), and those with non-immunocompromising conditions (35, 21.2%). Comparison of immunocompetent and immunocompromised children revealed that complication of VZV infection was a more common reason for admission among the former (86 of 105, 81.9%, P<0.001), whereas treatment with acyclovir to limit dissemination was the most common reason in the latter (53 of 60, 88.3%, P<0.001). Skin and soft tissue infections were the most common complications in immunocompetent children (36 of 98) and those younger than five years (26 of 53), whereas pulmonary complications predominated among immunocompromised patients (eight of 98) and neurological complications in five- to 10-year-olds (16 of 36). Only one death (0.6%) occurred in an immunocompetent patient. Group A beta-hemolytic streptococci and Staphylococcus aureus caused equal numbers of secondary infections (92% of all isolates). CONCLUSIONS: Complications of VZV infections and secondary prophylactic antiviral treatment of immunocompromised children explain the majority of hospitalizations in this institution, and can be monitored after VZV vaccine introduction. Complications vary significantly with underlying healthy status and age.