Varicella zoster virus and safe in adults with Human Immunodeficiency Virus. Chickenpox-like rashes were recognised and described by ancient civilizations; the relationship between zoster and chickenpox was not realized until 1888. It was in 1943 that Ruska noticed the similarity between virus particles isolated from the lesions of zoster and those from chickenpox. In 1974 the first vaccine was introduced for chickenpox. Varicella zoster virus Varicella zoster virus or varicella-zoster virus (VZV) is one of eight herpesviruses known to infect humans. It causes chickenpox (varicella), a disease most commonly affecting children, teens, and young adults, and shingles (herpes zoster) in adults; shingles is
Rare disease treated, are excluded from their definition. The definitions used in the medical literature and by national health plans are similarly divided, with definitions ranging from 1/1,000 to 1/200,000. Because of definitions that include reference to treatment availability, a lack of resources, and severity of the disease, the term "orphan disease" is used as a synonym for "rare disease". But in the United States and the European Union, "orphan diseases" have a distinct legal meaning. The United States' Orphan Drug Act includes both rare diseases and any non-rare diseases "for which there is no reasonable expectation that the cost of developing