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Varicella / Chickenpox
1996 Case Definition

Clinical Description

An illness with acute onset of diffuse (generalized) papulovesicular rash without other apparent cause

Laboratory Criteria for Diagnosis

  • Isolation of varicella virus from a clinical specimen, OR
  • Significant rise in serum varicella immunoglobulin G antibody level by any standard serologic assay

Case Classification


A case that meets the clinical case definition, is not laboratory confirmed, and is not epidemiologically linked to another probable or confirmed case


A case that is laboratory confirmed or that meets the clinical case definition and is epidemiologically linked to a confirmed or probable case


Two probable cases that are epidemiologically linked would be considered confirmed, even in the absence of laboratory confirmation.