Assessing Immunity to Varicella

Evidence of immunity to varicella includes any of the following:

• Documentation of age-appropriate varicella vaccination;
  • Preschool-age children (i.e., age 12 months through 3 years): 1 dose
  • School-age children, adolescents, adults: 2 doses
• Laboratory evidence of immunity or laboratory confirmation of disease
• Birth in the United States before 1980 (Should not be considered evidence of immunity for health care personnel, pregnant women, and immunocompromised persons)
• Diagnosis or verification of a history of varicella or herpes zoster by a health care provider

To verify a history of varicella, health care providers should inquire about:

• an epidemiologic link to another typical varicella case or to a laboratory confirmed case, or
• evidence of laboratory confirmation, if testing was performed at the time of acute disease

Persons who have neither an epidemiologic link nor laboratory confirmation of varicella should not be considered as having a valid history of disease. For these persons, a second dose of vaccine is recommended if they previously received only one dose. If a health care provider verifies the diagnosis based on the above criteria, then vaccination is not needed.