Can the salience of mandatory restrictions curb vaccine hesitancy? A comparison between Italy and Spain

Vaccine hesitancy is a crucial issue in most advanced Countries. The matter gained even greater importance in the aftermath of the pandemic, during which the implementation vaccine campaigns was an emergency topic of public health. Policy makers and experts have still kept under scrutiny the consequences of digital COVID-19 certificates, and their requirement as pre-requisite for many daily activities (e.g., enter public indoor spaces or use public transport). This paper focuses on two European countries which adopted very different measures in this respect: Spain and Italy. In Spain, Galicia and Canary Islands only required at first the proof of vaccination, testing or recovery to visit indoor public spaces. A few months later however, some Spanish Superior Courts of Justice abrogated the mandatory use. However, following the increased burden of COVID-19, eleven Spanish regions received court approval to make the certificate a requirement to enter specific spaces. In Italy, since its introduction in June 2021, the mandatory use of COVID-19 certificates was announced by the Italian prime minister at various dates, eventually resulting into mandatory vaccination for individuals aged 50 at the end of 2021. We sketch a model of the effect of announcing policy restrictions on vaccine hesitancy, and test the impact of the digital COVID-19 certificate salience on vaccination rates through a sharp regression kink design estimator and a Difference-in-Differences strategy. Our results reveal that the digital COVID-19 certificate increased vaccinations in Italy in a range spanning from 2.01 to 6.93 percent. The two announcements that mostly increased vaccinations are the first one, i.e., the COVID-19 digital certificate introduction, and the imposition of mandatory vaccinations for individuals over 50. In Spain by contrast, only the last announcement seems to have been able to affect vaccinations. Keywords: COVID-19 digital certificate, policy salience, sharp regression kink design, vaccine hesitancy JEL Classification: I12, I18