. Varicella zoster virus (VZV) is a virus that causes chickenpox in children and shingles in unvaccinated people.
. VZV is highly contagious and is transmitted through contact with fluid from ruptured blisters or respiratory secretions of infected people.
. Immunity after infection is usually lifelong, although the virus remains latent in the sensory nerve ganglia, where it can reactivate, causing shingles when immunity decreases due to aging or immunosuppresion.
. A positive IgM result typically indicates a current or recent infection, such as chickenpox, or reactivation in the form of shingles, while IgG antibodies serve as an indicator of past infection or successful vaccination.