Outbreak of varicella in a pediatric oncology unit

Varicella-zoster virus (VZV) infection is usually benign but immunocompromised patients are at great risk for visceral dissemination and fatal outcome. During a nationwide varicella outbreak, several of our patients contracted the disease. We undertook studies of the epidemiology and the efficacy of antiviral treatment and immunoprophylaxis.

During a 9-month period, 52 patients were exposed to cases of active varicella. Twenty-seven of these children were reexposed to active varicella > 1 month after their initial exposure. The exposure concerned 7 VZV waves of varying intimacy. In all cases, prophylaxis with intravenous immunoglobulin (IVIG), varicella zoster globulin (VZIG), or both was given. The spread of the disease was limited and only 6 patients (all immunosuppressed) developed varicella (7.6%). Three of 6 had been given IVIG and 3 VZIG + IVIG. All patients with varicella received acyclovir 30 mg/kg/day for 14 days. The disease was mild and all patients were ultimately cured.

Our results show that prophylaxis was not 100% effective, but appearance to reduce the rate of spread. The differences in incidence among the regimens used were not significant.

For the moment, immunoprophylaxis and acyclovir administration appear to be quite satisfactory in managing immunocompromised children exposed to VZV. This may change with the wider use of the varicella vaccine.