Should a child who has already had chickenpox (varicella) receive the varicella vaccine?

Varicella Vaccination in a Child with Prior Chickenpox Infection

Varicella vaccine should be withheld in children with documented history of chickenpox infection, as they already have immunity to varicella-zoster virus (VZV). 1

Evidence of Immunity to Varicella

• Documentation of immunity to VZV includes laboratory evidence of immunity, laboratory confirmation of disease, or history of varicella disease verified by a healthcare professional 1
• For patients with typical disease presentation, verification can be performed by any healthcare professional (physician, nurse practitioner, physician assistant) 1
• In this case, the pediatrician has confirmed the diagnosis of chickenpox based on the typical rash presentation documented in photos shown by the mother 1

Rationale for Withholding Vaccination

• Prior infection with varicella provides natural immunity, making vaccination unnecessary 1
• The American Academy of Pediatrics guidelines clearly state that evidence of immunity includes documented history of varicella disease verified by a healthcare professional 1
• The purpose of vaccination is to provide immunity in susceptible individuals who have not been previously infected 2

Approach to Determining Varicella Immunity

For patients with reported history of chickenpox:

1. Verify through healthcare professional documentation 1
2. For typical disease presentations, any healthcare professional can verify immunity 1
3. For atypical or mild cases, physician assessment is recommended with either:
   • Epidemiologic link to a typical or laboratory-confirmed case, or
   • Laboratory confirmation if performed during acute illness 1

Special Considerations

• In cases where documentation of prior infection is uncertain or unavailable, serologic testing can be performed to confirm immunity, though this is generally not necessary with clear documentation 1
• While vaccination of someone already immune is not harmful, it is unnecessary and not recommended as standard practice 3
• The Centers for Disease Control and Prevention recommends that children who have already had chickenpox do not need varicella vaccination 2

Potential Pitfalls

• Misdiagnosis of prior "chickenpox-like" rashes that were actually other conditions could lead to incorrect assumptions about immunity 1
• In this case, the diagnosis was confirmed by a physician who observed the typical varicella rash, providing reliable evidence of immunity 1
• Self-reporting of varicella disease has become less reliable in the vaccine era, but this case involves physician documentation, which is considered valid evidence of immunity 1

Algorithm for Decision-Making

1. Has the child had chickenpox confirmed by a healthcare provider? Yes → Vaccine should be withheld
2. Is there photographic or laboratory evidence supporting the diagnosis? Yes → Vaccine should be withheld
3. Is there uncertainty about the diagnosis? No → Vaccine should be withheld

In this case, the 18-month-old child has physician-confirmed chickenpox with photographic evidence, providing clear documentation of immunity, making varicella vaccination unnecessary 1.