Should an 18-month-old child with a confirmed history of chickenpox (varicella) receive the varicella vaccine?

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Last updated: February 4, 2026View editorial policy

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Varicella Vaccine Should Be Withheld in This Child

A child with documented, healthcare provider-verified history of chickenpox does not need varicella vaccination, as natural infection provides lifelong immunity that is superior to vaccine-induced immunity. 1

Evidence of Immunity Eliminates Need for Vaccination

The key factor in this case is that the child has confirmed varicella disease verified by a healthcare provider (the pediatrician diagnosed chickenpox and the mother showed typical varicella rash pictures). This constitutes valid evidence of immunity. 1

  • A documented history of varicella disease verified by a healthcare provider is explicitly recognized as evidence of immunity and is a valid reason to withhold varicella vaccination. 1
  • The ACIP (Advisory Committee on Immunization Practices) has approved criteria for evidence of immunity that include "a diagnosis of varicella by a health-care provider or a health-care provider verification of a history of disease." 2
  • Natural varicella infection provides lifelong immunity that is superior to vaccine-induced immunity. 1

Why Other Options Are Incorrect

Postponing until age 2 years (Option B) is unnecessary because:

  • The issue is not about timing—the child already has immunity from natural infection. 1
  • Even if the child were susceptible, varicella vaccine is routinely recommended starting at 12-15 months of age, not delayed until 2 years. 1

Giving the vaccine now (Option C) is inappropriate because:

  • Vaccinating individuals with documented immunity provides no additional benefit and wastes resources. 1
  • The child at 18 months has already achieved natural immunity, which is more robust than vaccine-induced immunity. 1

Giving vaccine plus immunoglobulin (Option D) is incorrect because:

  • Immunoglobulin is only indicated for post-exposure prophylaxis in susceptible individuals within 96 hours of exposure, not for children who have already recovered from the disease. 1
  • This child is no longer susceptible and does not require any intervention. 1

Critical Documentation Point

  • Ensure documentation of the verified varicella history is placed in the medical record to prevent future unnecessary vaccination attempts. 1
  • Only written documentation of healthcare provider verification should be considered valid evidence—parental reporting alone is insufficient, particularly in young children where the positive predictive value is only 75% in unvaccinated children aged 12 months-4 years. 2

Common Pitfall to Avoid

Do not confuse this scenario with catch-up vaccination schedules for unvaccinated children—a child with documented natural disease is fundamentally different from being unvaccinated but susceptible. 1

Answer: A. Varicella vaccine withheld

References

Guideline

Varicella Vaccine Administration Guidelines

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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