The Impact of Mandatory Vaccination Law in Italy on MMR Coverage Rates in Two of the Largest Italian Regions (Emilia-Romagna and Sicily): An Effective Strategy to Contrast Vaccine Hesitancy

Background: Vaccine hesitancy has increased worldwide, leading to reduction in vaccination coverage rates. In particular, reduction in the coverage for the trivalent Measles-Mumps-Rubella vaccine has led to an increase of measles cases. The aim of this study is to analyze the coverage rates for the MMR vaccine in the Emilia-Romagna Region (RER) and Sicily Region (SR) between 2009 and 2018, and to correlate any significant change to index events which could have modified the trend of vaccination rates. Methods: Official aggregate data on vaccination coverage at 24 months provided by the RER and the SR were analyzed through trend analysis and related to important index events. Results: The two regions showed similar results; both achieved the lowest coverage rates in 2015 and both showed an increase in the rates after the introduction of mandatory vaccinations for access to schools. In 2018, both reached the starting point before the decrease. Conclusions: Our results confirm the effectiveness of legislative coercive measures in favor of vaccination. A potential decrease in the coverage rates may be observed as a result of an attenuation of the positive effects of coercive measures over time. It is thus necessary to combine these measures together with information campaigns and political initiatives at different levels (i.e., national, regional).