An ecological analysis of socio-economic determinants associated with paediatric vaccination coverage in the Campania Region: A population-based study, years 2003-2017.

INTRODUCTION: Vaccines are the most cost-effective and straightforward intervention against severe infectious diseases. However, in Europe and in Italy, paediatric vaccination coverage for certain vaccines remains suboptimal, with considerable regional differences in Italy. Vaccine coverage varies significantly due to socio-economic and organisational factors. Aim of this study was to assess the influence of the Deprivation Index, the density of General Practitioners and General Paediatricians per inhabitants on the coverage of both mandatory and non-mandatory paediatric vaccinations across local health authorities and health districts in the Campania Region for birth cohorts from 2001 to 2015.

MATERIALS AND METHODS: Population-based, ecological time series analysis focusing on the Campania Region, most populous region in the south of Italy. Vaccination coverage data were extracted from the regional immunization database, whilst information on the Deprivation Index and number of primary care doctors and primary care paediatricians per local health district were extracted from public health records. Univariate descriptive statistics were employed to describe study characteristics, as appropriate, whilst and mixed-effect linear regression models were employed to assess the associations between variables of interest and vaccination coverage.

RESULTS: Overall vaccination coverage has generally increased, except for the MMR vaccine, which showed coverage fluctuations. An increase in the Deprivation Index, indicative of less favourable socio-economic conditions, was associated with decreased vaccination coverage in the 24-month age group for some mandatory vaccines (DTaP: Coef -0.97, 95% CI -1.77 | -0.17; Poliomyelitis: Coef -0.98, 95% CI -1.78 | -0.17; Hepatitis B: Coef -0.90, 95% CI -1.71 | -0.10). Moreover, areas with a greater density of General Paediatricians per inhabitants saw increased coverage for Haemophilus influenzae type b in the 6-year age group (Coef 9.78, 95% CI 1.00 | 18.56).

CONCLUSIONS: It is necessary to target public health policies to address vaccination inequalities. These efforts should include expanding vaccination campaigns, enhancing catch-up programs, and increase resource allocation in primary care settings to facilitate the role of General Practitioners and Paediatricians in fostering awareness and adherence.