The varicella vaccination programme decreases the rate of pediatric severe varicella, but it does not change herpes zoster related hospitalizations

In a recently published study of the impact of different varicella vaccination strategies in Spain¹, the authors conclude that severe varicella infections have decreased since routine varicella vaccination in Spain (2006). This decrease was significantly higher in regions including the vaccine at 15–18 months of age compared with those vaccinating only susceptible adolescents. The hospitalization rate related to herpes zoster slightly increased (mainly in the >84 age group). No significant differences were found in herpes zoster hospitalization rates regarding the varicella vaccination strategies among regions.

After the critical appraisal of this study, it can be said that the incidence of severe varicella is actually reduced with varicella vaccination of susceptible adolescents. This benefit doubles vaccinating children at 15-18 months of age. The incidence of severe zoster is steadily growing, especially in the elderly. Although there is no evidence of a causal link with the vaccine, this issue is essential to establish the varicella vaccination social cost-effectiveness.