Skip directly to site content Skip directly to search
U.S. flag An official website of the United States government

Official websites use .gov

A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS

A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

NOTE: A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.

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.

Related Case Definition(s)