Determinants of inequality in the up-to-date fully immunization coverage among children aged 24-35 months: Evidence from Zhejiang province, East China.

OBJECTIVE: This study aimed to determine the degree and determinants of inequality in up-to-date fully immunization (UTDFI) coverage among children of Zhejiang province, east China.
METHOD: We used data from the Zhejiang provincial vaccination coverage survey of 2014 and the health outcome was the UTDFI status among children aged 24-35 months. The household income per month was used as an index of socio-economic status for the inequality analysis. The concentration index (CI) was used to quantify the degree of inequality and the decomposition approach was applied to quantify the contributions from demographic factors to inequality in UTDFI coverage.
RESULTS: The UTDFI coverage was 80.63% and the CI for UTDFI coverage was 0.12028 (95% CI: 0.10852-0.13175), indicating that immunization practice significantly favored children with relatively higher socio-economic status. The results of decomposition analysis suggested that 68.2% of the socio-economic inequality in UTDFI coverage should be explained by the mother's education level. Furthermore, factors such as birth order, ethnic group, maternal employment status, residence, immigration status, GDP per-capital and percentage of public health spending of the total health spending also could explain the disparity in UTDFI coverage.
CONCLUSION: There exists inequality in UTDFI coverage among the socio-economic disadvantage children. Health interventions of narrowing the socio-economic inequality in UTDFI coverage will benefit from being supplemented with strategies aimed at poverty and illiteracy reduction.