Impact of universal vaccination against varicella in Italy

Abstract

In Italy, the introduction of Universal Varicella Vaccination (UVV) has been decided but postponed, as a national programme, until 2015, when data from Regions which have already implemented it will be available. Starting from 2003, eight Italian Regions (Basilicata, Calabria, Friuli Venezia Giulia, Apulia, Sardinia, Sicily, Tuscany and Veneto) have progressively introduced UVV, in their immunization programme, with different schedules in children aged 13-15 months and 5-6 years, currently a two-dose schedule is adopted by all Regions. In June 2013, an Interregional Group on Varicella Vaccination (IGVV) has been established in order to assess the effectiveness of varicella vaccination with standardized and shared tools. The aim of this study was to evaluate the impact of varicella vaccination on the incidence and hospitalizations due to varicella and its complications in the period 2003-2012 in order to support the Italian decision makers on the future national adoption. Preliminary data showed that a general reduction of incidence and hospitalization rates was observed in the study period, resulting in relevant savings for the National Health Service. Immunization coverage with first dose at 24 months of age was high in all Regions (84%-95%) in 2012. Adverse events due to varicella vaccines were rare and without permanent sequelae. Underreporting of varicella cases and delays in the administration of the first dose of varicella vaccines were the main critical issues. In conclusion, solid evidences in support of universal UVV arise from the experiences available today in Italy.

Keywords: Universal Varicella Vaccination; Varicella; adverse events following varicella immunization; hospitalizations; immunization coverage; notifications.

Figure 1. Varicella incidence rates (×1000) in 8 Italian Regions, before and after the time “zero” of Universal Varicella Vaccination introduction (time “zero” being the year of start of varicella vaccination implementation, which is different in the different Regions).

Figure 2. Varicella notifications, incidence rates and estimated incidence rates, assuming a 5-fold underreporting rate in the IGVV Regions (2003–2012). (Note: 95% CI for estimated incidence rates are reported in square brackets).

Figure 3. Hospitalizations and annual hospitalization rates due to varicella complications (×100 000) in 8 Italian Regions (2003–2012). [Tuscany: data not available for 2003; Calabria: data not available for 2003 and 2004] (Note: 95% CI for hospitalization rates are reported in square brackets).

Figure 4. Total annual costs of hospitalizations due to varicella, as primary and secondary diagnoses, in 6 Italian Regions (2003–2012) (Tuscany and Veneto: data not available for 2003; Sardinia and Calabria: data not available for the entire period).