Background of the antigen
Varicella Zoster Virus (VZV), a member of the human herpes virus family, causes two distinct clinical manifestations: childhood chickenpox(Varicella) and shingles (zoster). Varicella is the outcome of the primary infection with VZV, whereas, zoster is the result of VZV reactivation from latently infected sensory ganglia which occurs predominantly in aging and immunosuppressed individuals.VZV virons are spherical and 150-200 nm in diameter. Its lipid envelope encloses the nucleocapsid of 162 capsomeres arranged in a hexagonal form. Its DNA is a single linear, double strand molecule, 125,000 nt long.