Varicella Vaccine Names
The varicella vaccine is available in the United States as VARIVAX (brand name) which contains live attenuated Oka/Merck strain of varicella-zoster virus as its generic component. 1, 2
Details of Varicella Vaccines
Single-Antigen Varicella Vaccine
- Brand name: VARIVAX
- Manufacturer: Merck & Co., Inc.
- Generic component: Live attenuated Oka/Merck strain of varicella-zoster virus
- Formulation: Lyophilized preparation containing a minimum of 1350 plaque-forming units (PFU) of Oka/Merck varicella virus per 0.5 mL dose when reconstituted 1, 2
- Licensed for: Individuals 12 months of age and older 1
Combination Vaccine
- Brand name: ProQuad (MMRV)
- Manufacturer: Merck & Co., Inc.
- Components: Combines varicella vaccine with measles, mumps, and rubella vaccine
- Varicella component: Contains a higher concentration of Oka/Merck VZV (minimum 3.99 log10 PFU) compared to VARIVAX 1
- Licensed for: Children 12 months through 12 years of age only 1
Vaccine Composition
VARIVAX contains:
- Minimum of 1350 plaque-forming units (PFU) of Oka/Merck varicella virus
- 24 mg of sucrose
- 12.0 mg hydrolyzed gelatin
- 3.1 mg of sodium chloride
- 0.5 mg of monosodium L-glutamate
- 0.44 mg of sodium phosphate dibasic
- 0.08 mg of potassium phosphate monobasic
- 0.08 mg of potassium chloride
- Trace amounts of residual components from MRC-5 cells (DNA and protein)
- Trace quantities of neomycin and fetal bovine serum
- No preservatives 2
Historical Context
VARIVAX was first licensed in the United States in 1995 as the first vaccine to prevent chickenpox. Since then, more than 55 million doses have been distributed in the United States 1. The vaccine was developed from the Oka strain of varicella virus, which was initially isolated in Japan and then further attenuated through sequential propagation in various cell cultures, including human embryonic lung cells, embryonic guinea-pig cells, and human diploid cells (WI-38), with further passages in human diploid-cell cultures (MRC-5) for a total of 31 passages 1.
In 2005, the combination MMRV vaccine (ProQuad) was licensed, providing protection against measles, mumps, rubella, and varicella in a single injection 1.
Effectiveness
The varicella vaccine is highly effective, with:
- Single-dose effectiveness of approximately 85% in preventing varicella disease of any severity 1
95% effectiveness in preventing severe varicella disease 1
- Two-dose regimen showing 98.3% efficacy over a 10-year observation period (compared with 94.4% for 1 dose) 3
The Advisory Committee on Immunization Practices (ACIP) now recommends a routine 2-dose varicella vaccination schedule for children, with the first dose at 12-15 months and the second dose at 4-6 years of age 1.