[Is it necessary to vaccinate against varicella?].

Varicella is a frequent viral disease, with a substantial medical and societal impact. For many years, various industrialized countries have adopted an universal mass vaccination against varicella, using a one-dose schedule. In these countries, the global incidence of varicella has decreased by about 90%. A significant reduction in hospitalizations, outpatient visits and medical costs due to varicella has also been observed. Recently, a 2-dose schedule has demonstrated an efficacy of about 98%, as well as herd immunity.