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VZV infection: epidemiology and prevention.

Varicella is an infectious disease caused by a virus (VZV), identified almost a century ago, belonging to herpesvirus family [1]. The disease mostly affects younger age classes. Although considered a mild disease, in some cases, especially in immunocompromised subjects, varicella can be severe, even fatal. The clinical course of the disease is longer in adults and more severe than in childhood [2]. VZV infection in susceptible pregnant woman, although rare, can cause severe forms both in the mother and in the newborn. A disabling congenital or neonatal varicella syndrome can affect the offspring born to a woman who contracts VZV during pregnancy [3]. During primary infection, VZV has the ability to become latent in the sensory-nerve ganglia and to cause, many years later, the reactivated form, herpes zoster [4]. The epidemiological relevance of varicella and the availability of a live, attenuated, safe and effective vaccine [5, 6], have prompted an ample international debate on the opportunity of extensive infant varicella vaccination. Recently, a new high-potency, live, attenuated varicella zoster vaccine has demonstrated able to reduce morbidity and complications associated to zoster [7].