The clinical and economic costs associated with regional disparities in varicella vaccine coverage in Italy over 50 years (2020-2070).

Italy implemented two-dose universal varicella vaccination (UVV) regionally from 2003 to 2013 and nationally from 2017 onwards. Our objective was to analyze regional disparities in varicella outcomes resulting from disparities in vaccine coverage rates (VCRs) projected over a 50-year time-horizon (2020-2070). A previously published dynamic transmission model was updated to quantify the potential public health impact of the UVV program in Italy at the national and regional levels. Four 2-dose vaccine strategies utilizing monovalent (V) and quadrivalent (MMRV) vaccines were evaluated for each region: (A) MMRV-MSD/MMRV-MSD, (B) MMRV-GSK/MMRV-GSK, (C) V-MSD/MMRV-MSD, and (D) V-GSK/MMRV-GSK. Costs were reported in 2022 Euros. Costs and quality-adjusted life-years (QALYs) were discounted 3% annually. Under strategy A, the three regions with the lowest first-dose VCR reported increased varicella cases (+ 34.3%), hospitalizations (+ 20.0%), QALYs lost (+ 5.9%), payer costs (+ 22.2%), and societal costs (+ 14.6%) over the 50-year time-horizon compared to the three regions with highest first-dose VCR. Regions with low first-dose VCR were more sensitive to changes in VCR than high first-dose VCR regions. Results with respect to second-dose VCR were qualitatively similar, although smaller in magnitude. Results were similar across all vaccine strategies.

The Cost-Effectiveness of Universal Varicella Vaccination in Italy: A Model-Based Assessment of Vaccination Strategies.

BACKGROUND: In 2017, varicella vaccination became mandatory for all children in Italy, based on a two-dose schedule administered at 12-15 months of age and 5 to 6 years of age. Varicella vaccines are available in different formulations (as a single vaccine or as a combination vaccine together with measles, mumps, and rubella) and are made by multiple manufacturers with different effectiveness profiles. This study calculates the cost-effectiveness of a range of varicella vaccination strategies to identify the optimal strategy for Italy. METHODS: A dynamic transmission cost-effectiveness model was applied in Italy to simulate the long-term (50 years) costs and outcomes associated with different varicella vaccination strategies. Five vaccination strategies were evaluated using the model: two doses of two different combination Measles-Mumps-Rubella-Varicella vaccines (either Vaccine A (MSD) [denoted QQVa] or Vaccine B (GSK) [denoted QQVb]); a first dose of a single Varicella vaccine followed by a second dose of a combination vaccine (either Vaccine C (MSD) followed by Vaccine A [denoted MQVa] or Vaccine D (GSK) followed by Vaccine B [denoted MQVb]); or no vaccine at all (NV). The model was adapted for Italy using publicly available Italian data and expert opinion. RESULTS: Over the 50-year time-horizon, in the absence of universal varicella vaccination, there would be 34.8 million varicella cases, 142 varicella-infection-related deaths, and €23 billion in societal costs. The cost per capita from a societal perspective ranged from €164.55 to €392.18 with NV being the most expensive and QQVa the least expensive. The most effective strategy was QQVa, which resulted in a 66% decrease in varicella cases and 30% reduction in varicella-related deaths compared to NV strategy. QQVa led to a net saving in societal cost around €13 billion compared to NV as the cost of vaccination was more than offset by the savings that resulted from the reduced burden of illness. CONCLUSION: Varicella vaccination has a major impact on reducing varicella incidence, prevalence, and societal costs. This analysis supports the policy for universal varicella vaccination in Italy as the NV strategy was the most expensive and resulted in the poorest outcomes. QQVa offers the greatest benefits at the lowest cost and should be considered as a potential priority strategy for Italian population.