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 nonimmunocompromising 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.

Keywords: Childhood; Complications; Varicella zoster infections.

Figure 1

Reason for admission to hospital with varicella zoster infections by patient health status. Nonimmunocompromising conditions include eight endocrinopathies (two panhypopituitarism, two congential adrenal hyperplasia, four insulin-dependent diabetes melllitus), six skin disorders (four eczema, one burn, one lamellar icthyosis), four seizure disorders, four congential heart disorders, three asthmatics, three infants born prematurely, portal hypertension, polycystic kidneys, recurrent severe emesis of unknown etiology, chronic idiopathic thrombocytopenic purpura, chromosomal anomaly, cystic fibrosis and mononucleosis. Immunocompromising conditions include acute lymphocytic leukemia (22), acute myeloblastic leukemia (one), lymphoma (three), solid tumour (12), immunosuppressive doses of steriods for nonmalignant conditions (16), bone marrow transplant (two), liver transplant (one), hypogammaglobulinemia/neutropenia (one), ataxia-telangiectasis (one) and neonate (one). *Comparisons made between immunocompetent (healthy and nonimmunocompromised conditions) and immunocompromised patients. Chronic skin disease (one of each eczema, lamellar icthyosis), V-1 zoster with underlying portal hypertenion (one), endocrinopathies for which replacement doses of corticosteriods were given (four), and congential heart disease (two)

Figure 2

Sites of varicella zoster virus complications leading to admission, by patient health status group. *Comparisons made between immunocompetent (healthy and nonimmunocompromising conditions) and immunocompromised patients. CNS Neurological complications; SST Skin and soft tissue infection

Figure 3

Anatomical sites among patients with complications by patient age group. *Comparisons were made between children younger than five years of age and children aged five to 10 years, given the small number of children older than 10 years of age. CNS Neurological complications; SST Skin and soft tissue infection