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Introduction: In the Veneto Region of Italy, universal varicella vaccination (VV) started in 2007 with a two-dose schedule at 12-15 months and 5-6 years of age achieving 90 % coverage in 2019. The study aimed at evaluating the vaccine effectiveness (VE) in children using a primary-care database METHODS: This retrospective analysis used Pedianet, a comprehensive database of 73 family paediatricians in the Veneto Region. Incidence rates (IR) of varicella were evaluated in children aged <14 years enrolled since birth, between January 2004 to April 2022. Cases were classified as breakthrough if happening beyond 42 days post-VV. Complications and prescription were evaluated. Subject were followed up from 2004 or the enrollment date, until the end of assistance/study or the first or second VV dose. Kaplan-Meier curves and log-rank tests were used to compare the varicella incidence by vaccination status. Hazard ratios of varicella infection, adjusted (aHRs) for sex, vaccinal status, age group, prematurity and socioeconomic status were estimated with Cox's regression. VE for one and two VV doses was defined as 1-aHR*., Results: 36,498 children, followed for 233,508 person-years from 2004 to 2022 experienced 1006 cases of varicella (13 complicated and 35 breakthrough). Younger children had a higher risk of experiencing varicella compared to children aged >7 years, irrespective of their vaccination status. Indeed, the IR increased from 5.5 to 19.5 × 1000 person-years and from 1.1 to 5.4 × 1000 person-years in unvaccinated and vaccinated children aged <12 months versus those aged 5-6 years, respectively. Varicella VE was 83.4 % and 94.7 % in those vaccinated with one and two doses. After six years, the cumulative probability of experiencing varicella was 10.7 % for unvaccinated subjects, and 2.5 % and 0.4 % for those vaccinated with one and two-doses (log-rank test, p < 0.001)., Conclusions: Two-dose schedule VV is effective in drastically reduce varicella episodes. Breakthrough varicella episodes remain rare events., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Societa’ Servizi Telematici reports financial support was provided by Merck Sharp & Dohme LLC. Elisa Barbieri reports financial support was provided by Ministero dell'Istruzione, universita’ e ricerca (MIUR). If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

It is strategically important to monitor the safety profile of vaccination schedules in order to achieve and maintain high levels of coverage. We analyzed the cohort of individuals actively invited for measles, mumps, rubella and varicella (MMRV) vaccination in the Veneto region (north-east Italy) from 8/1/2013 to 7/31/2014, assessing the onset of adverse events (AE) relating to 2 different vaccination strategies for MMRV (MMR+V vs MMRV). During the vaccination session at 14 months old, parents were given a form for recording local and systemic reactions to vaccinations for 4 weeks afterwards. Overall, 12,288 forms were returned, and 84.6% of them were included in this analysis (5,130 relating to MMR+V and 5,265 to MMRV); 37.3% of the sample reported no AEs, with no difference between the 2 groups. Local reactions were more common in the MMR+V group (9.6% vs 2.9%; RR 3.33; 95% CI 2.79-3.98), while there was no difference in general reactions between the 2 groups (50% MMR+V vs 52% MMRV). The events most often reported were "fever <39.5°C," which was more frequently associated with the MMRV strategy (p<0.001), and "skin blotches and marks," which occurred more often in the MMR+V group (p<0.001). Reports of "fever ≥39.5°C" were equally distributed between the 2 groups. Sixteen cases of febrile seizures were reported (0.14% in the MMR+V group and 0.17% in the MMRV group). Similar safety profiles were identified for the 2 vaccination strategies. Although the method used to record reactions to vaccination demanded considerable resources, it enabled important information to be collected on parents' perception of the AEs occurring in response to their child's vaccination.

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.