Temporal trends in herpes zoster-related hospitalizations in Italy, 2001-2013: differences between regions that have or have not implemented varicella vaccination

Background: Herpes zoster (HZ) has a relevant impact on the population in terms of incidence and complications. Aims: The aim of this study was to estimate the HZ-related hospitalization rates in Italy in the period 2001–2013, and to evaluate the trend of hospitalizations in the course of time pointing out any differences between regions that have or have not introduced universal childhood varicella immunization (UVI). Methods: A retrospective analysis was conducted on hospital discharge records contained in the national database of the Ministry of Health for the period January 2001– December 2013. The comparison of hospitalization rates of "pilot" versus "not pilot" regions was performed taking into account as "pilot" regions the three that first introduced UVI (Sicily, Veneto, and Apulia). The average annual percentage change in hospitalization rates was used to highlight any significant change in time trends. Results: In the period 2001–2013, 93,808 HZ-related hospitalizations were registered altogether. Complicated HZ was diagnosed in 53.2% of cases; a relevant part (32.5%) of hospitalizations involved subjects with at least one co-morbidity. In the three Italian "pilot" regions, a greater decrease of HZ-related hospitalization rates occurred in comparison to other regions. Discussion: A good understanding of the epidemiology of HZ disease is required to assess the overall impact of the varicella immunization programs and to establish the most appropriate health strategies against HZ. Conclusions: The data obtained confirm the epidemiological impact of HZ and its complications and the need of a preventive approach.