[Priorix Tetra: a new combined vaccine against measles, rubella, mumps and varicella].

Varicella is an infectious disease caused by a virus of the herpes virus family (VZV) affecting predominantly the pediatric age. Varicella is considered a mild disease, but in some cases, mainly in immunocompromised subjects, it can evolve towards complicated cases, even fatal. In immunocompetent subjects, however, serious complications can also arise, such as cutaneous bacterial superinfections, pneumonia, conjunctivitis or corneal infections and central nervous system (CNS) complications. The rate of hospitalization, even in developed countries, is high. Due to the epidemiological relevance of varicella, the availability of a live, attenuated, safe and effective vaccine, has prompted an international debate on the opportunity of extensive infant varicella vaccination, that could be overcome by the introduction of the combined tetravalent vaccines against measles, mumps, rubella and varicella (MMRV). Priorix Tetra, a new quadrivalent MMRV vaccine produced by GlaxoSmithKline, has demonstrated high immunogenicity, comparable to that of the separate vaccines (Priorix and Varilrix) in addition to a favorable tolerability and safety profile. This review summarizes the epidemiology of measles, mumps, rubella and varicella in Italy, encompassing the rationale for the introduction of varicella vaccination and describes the immunological, clinical and safety profile of Priorix Tetra.