The 7 C Vaccination Readiness Scale: An Empirical Country Comparison Between Germany and Greece

Vaccinations are among the most effective interventions against infectious diseases such as measles, influenza, and COVID-19. Nevertheless, there are significant differences in vaccination readiness. The aim of this study was to validate the 7 C scale, which measures seven psychological factors comprising general vaccination readiness, in both German and Greek, and to investigate differences in vaccination behavior between a German and a Greek sample.

A cross-sectional study was conducted with a convenience sample of 576 study participants, of whom 319 responded to the online survey in German and 257 in Greek. Analyses included internal consistency, structural validity, construct validity through the known-groups method, item analysis, and floor and ceiling effects. The two samples differed significantly in terms of demographic data such as age, gender and education, as well as in religiosity and vaccination behavior.

The German sample showed a higher vaccination rate for most vaccinations, except for vaccinations against hepatitis A, varicella, and meningococcal disease, wheras in the Greek sample, there were significantly more "I don't know" responses regarding vaccination status. The 7 C scale of vaccination readiness demonstrated acceptable to good psychometric properties in terms of both internal consistency and construct validity in both samples, although there were some weaknesses in the component that measures calculation^R in both the 21-item and 7-item versions. The 7-component structure was confirmed using a confirmatory factor analysis. The German and the Greek samples differ primarily in the components confidence, complacency^R, and conspiracy^R, with significantly higher values in the German sample. Binary logistic regression analysis demonstrated that the 7 C scale had the lowest predictive value for measles vaccination and the highest for COVID-19.

The German and Greek versions of the 7 C scale are invaluable research tools for investigating vaccination readiness. A comprehensive understanding of the underlying factors contributing to vaccine hesitancy is imperative for the development of culturally tailored educational initiatives. These initiatives must be designed to address prevalent misconceptions regarding vaccination, with the objective of enhancing vaccination rates, and promoting public health.