Identifying Ferrara’s elderly people with low influenza immunization rates: the contribution of a local socio-economic deprivation index

Influenza immunization coverage rates remain far below the optimal value recommended by the World Health Organization, even in groups considered at high risk, such as the elderly. A possible explanation for this suboptimal vaccination uptake may be deprivation. A specifically developed local deprivation index was proposed for the classification of residents in the municipality of Ferrara in order to evaluate the characteristics of subjects over 65 years of age who accepted/refused influenza immunization (2010-2015). The variables building this deprivation index were primarily related to demographic aspects, such as age, widow/widower status, education, family composition and housing characteristics. Influenza immunization coverage rates were unsatisfactory in all categories of deprivation. A statistically significant decreasing trend in coverage rates was observed with decreasing deprivation in the general population and in males, but not in females. In addition to factors composing the local deprivation index, being separated, living in a family of three members and independent contractor were features that hindered immunization among very deprived elderly.