Exploring the effectiveness of the Digital Green Certificate Law as Public Health instrument to increase anti-COVID-19 vaccination in a sample of working-age adult population in the Palermo Metropolitan Area

Counteracting vaccine hesitancy should be considered an absolute priority for Public Health Authorities. A correct health communication represents one of the best ways to increase adhesion to vaccination among hesitant population. In order to increase vaccination coverage rates against COVID-19, the Italian government has issued a legislative decree with a mandatory “Digital Green Certificate” (DGC) to access workplaces for some categories considered at risk. Methods. We conducted a cross-sectional study with the aim to highlight the factors associated with the anti-COVID-19 vaccine acceptance and to estimate the influence of the introduction by law of the Digital Green Certificate (DGC) on the adhesion to the COVID-19 vaccination campaign in a sample of individual accessing one of the main vaccination centres of the metropolitan area of Palermo, Italy. An anonymous and validated questionnaire was self-administered through the Google Documents® platform, between October 2021 and March 2022. Results. Among the 467 subjects enrolled, 43.3% were influenced on their vaccination choice by the introduction of the DGC. The multivariate analysis showed that among the respondents emerged contrasting feelings with a self-reported significantly higher sense of freedom (Adj-OR = 2.45, 95%CIs = 1.51-3.97, p-value: < 0.001) but a lower sense of safety (Adj-OR = 0.19, 95%CIs = 0.12-0.29, p-value: < 0.001) after vaccine administration. Conclusions. Our findings, in line with the available literature, suggest that the introduction of DGC has led to a significant increase in the immunization rate and, together with an appropriate communicative approach, it could represent an effective strategy to counteract vaccine hesitancy.