Is varicella (chicken pox) vaccination necessary for healthy children?

Varicella Vaccination for Children

Yes, varicella (chickenpox) vaccination is necessary for all healthy children and should be administered as a two-dose series to provide optimal protection against the disease. 1

Vaccination Schedule

The recommended schedule for varicella vaccination in children includes:

• First dose: All healthy children should receive their first dose at 12-15 months of age 1
• Second dose: Should be administered at 4-6 years of age (before entering kindergarten or first grade) 1
• Minimum interval: The minimum interval between doses for children aged 12 months-12 years is 3 months 1
  • If the second dose is inadvertently given between 28 days and 3 months after the first dose, it is considered valid and does not need to be repeated 1

Vaccine Efficacy and Benefits

The two-dose varicella vaccination schedule provides significantly better protection than a single dose:

• One-dose efficacy: 80-85% effective against disease of any severity 1, 2
• Two-dose efficacy: 98% effective against any varicella disease and 100% effective against severe disease 1, 3

Breakthrough varicella (infection in vaccinated individuals) is:

• 3.3 times less likely with two doses compared to one dose 1
• Typically milder with fewer lesions when it does occur 3

Public Health Impact

Varicella vaccination has demonstrated significant public health benefits:

• Cost-effective: Both 1-dose and 2-dose varicella immunization programs are cost-saving at the societal level 1
• Reduced outbreaks: The second dose helps prevent outbreaks in school and other congregate settings 3, 4
• Shifted disease burden: The peak age-specific incidence has shifted from 3-6 year-olds to 9-11 year-olds in the post-vaccine era 1

Vaccine Options

Two vaccine formulations are available for children:

1. Monovalent varicella vaccine (Varivax): Approved for use in healthy persons aged ≥12 months 1
2. Combination MMRV vaccine (ProQuad): Approved only for children 12 months through 12 years of age 1

The American Academy of Pediatrics recommends using combination vaccines when all components are indicated to minimize the number of injections children receive 1.

Special Considerations

• Documentation of immunity: Only doses with written documentation of administration dates should be considered valid; self-reported doses or parental history alone is not adequate 1
• Contraindications: Include pregnancy, severe immunocompromise, high-dose systemic steroids, and severe allergies to vaccine components 3
• School entry requirements: The number of states requiring 2-dose varicella vaccination for elementary school entry increased from 4 in 2007 to 36 in 2012, helping to improve coverage rates 4

Potential Pitfalls

• Primary vaccine failure: Up to 24% of children may not develop detectable antibodies after a single dose, highlighting the importance of the second dose 2
• Breakthrough disease: Despite vaccination, outbreaks can still occur, particularly with the one-dose strategy 1
• Serologic testing: Pre-vaccination testing is generally not recommended for children without evidence of immunity 3
• Storage requirements: Both monovalent varicella and MMRV vaccines must be stored frozen at an average temperature of -15°C (5°F) or colder and used within 30 minutes after reconstitution 1

Varicella vaccination is a critical component of childhood immunization that significantly reduces morbidity and mortality associated with chickenpox while providing long-term protection against this highly contagious disease.