Varicella Vaccination After Prior Infection
A child with documented prior varicella infection does not need varicella vaccination, as natural infection provides evidence of immunity. 1
Evidence of Immunity
The American Academy of Pediatrics explicitly recognizes three forms of evidence of immunity to varicella-zoster virus in the pediatric population: 1
- Documentation of 2 appropriately timed doses of varicella vaccine (evidence grade I)
- Laboratory evidence of immunity or laboratory confirmation of disease (evidence grade I)
- Varicella diagnosed by a health care professional or verification of history of varicella disease (evidence grade III)
For a child with documented prior chickenpox infection verified by a healthcare professional, no varicella vaccination is required. 2
Verification Requirements
The reliability of varicella history depends on proper documentation: 1
For typical disease presentations: Any healthcare professional (school nurse, nurse practitioner, physician assistant, or physician) can verify immunity 1
For atypical or mild cases: Assessment by a physician or physician's designee is recommended, and one of the following should be documented: 1
- An epidemiologic link to a typical varicella case or laboratory-confirmed case
- Evidence of laboratory confirmation performed at the time of acute disease
History of herpes zoster diagnosed by a healthcare professional also constitutes evidence of immunity (evidence grade II-2) 1
Important Caveats About Self-Reporting
Parental self-reporting of varicella disease has become less reliable in the vaccine era. 1
- In the prevaccine era, 97-99% of adults with positive varicella history were seropositive 1
- In the vaccine era, only approximately 75% of unvaccinated children aged 1-4 years who report prior varicella infection are actually seropositive 1, 2
- This decreased reliability is likely due to decreased disease incidence and the proportion of mild breakthrough cases among vaccine recipients, which are less readily recognized 1
Therefore, healthcare professional verification is critical—parental report alone is insufficient. 1, 2
When Documentation is Lacking
If a child reports a history of varicella but lacks proper healthcare professional verification or documentation: 1
- Do not consider this as valid evidence of immunity
- Other diseases may mimic mild atypical varicella
- The child should receive the two-dose varicella vaccine series unless serologic testing confirms immunity
Serologic Testing Considerations
Serologic screening is generally neither necessary nor recommended if a person has acceptable evidence of immunity. 1
- People who lack adequate documentation of immunization or other evidence of immunity should be immunized without serologic testing 1
- Postimmunization serologic testing to verify immune response is not recommended, as available commercial assays are not sensitive enough and may give false-negative results 1
Clinical Bottom Line
Document the verified varicella history in the medical record to prevent future unnecessary vaccination attempts. 2 Natural varicella infection provides lifelong immunity that is superior to vaccine-induced immunity, making vaccination unnecessary and wasteful of resources in children with properly documented prior infection. 2