Varicella complications and universal immunization

Varicella is one of the most common infectious diseases, with a worldwide distribution.According to a WHO position paper, the global annual disease burden of varicella is estimated to be 140 million cases. 1 Despite the public perception of varicella infection as a harmless childhood affliction, it can be a very serious disease.As Martino Mota & Carvalho-Costa highlight in ''Varicella zoster virus related deaths and hospitalizations in Brazil before the introduction of universal vaccination with the tetraviral vaccine,'' varicella can cause death or can lead to potentially serious complications, which require hospitalization and eventually long-term sequelae.2 Varicella-related hospitalization rates differ widely worldwide.Varicella may potentially afflict any organ; hematological, neurological, respiratory, cutaneous, hepatic, gastrointestinal, urinary, and bone complications are the most frequently reported.3 The incidence of varicella complications differs among scientific reports.For example, the pooled prevalence of neurological complications resulting from a systematic review of the literature identifies the likelihood of pediatric neurological complications in the range of 13.9---20.4%. 4 Nevertheless, in some reports the rate of varicella neurological