Varicella-Zoster Virus Infections: Epidemiology, Diagnosis and Vaccine Safety

Abstract

Varicellovirus humanalpha3 (varicella-zoster virus; VZV), a member of the Orthoherpesviridae family, is a human pathogen that is widespread worldwide and has a preventive vaccine that has been used for decades. Primary infection causes chickenpox, in which VZV remains latent in ganglionic neurons after recovery. Primary VZV infection, which is generally associated with mild infections during childhood, can lead to severe and potentially life-threatening complications in newborns, immunocompromised individuals, or the elderly. In individuals whose cellular immunity against VZV decreases with advancing age or in immunocompromised individuals, VZV may reactivate and cause zoster. VZV vaccines, developed from live virus strains weakened by serial passages, have been added to national vaccination programs for the pediatric age group as single or double doses in many countries of the world, and have contributed to a significant decrease in VZV infections and associated complications throughout the world in the post-vaccination period. Apart from pediatric vaccines, live and recombinant herpes zoster vaccines have been developed and approved for use in adults aged 50 and over. Rare complications associated with VZV vaccines, which have been used safely for decades, may also occur. The main focus of this article is VZV vaccines, and in connection with these vaccines, it is aimed to provide an overview of the history, classification, epidemiology, clinic, complications, diagnosis, and treatment of VZV infections.