OBJECTIVES:Data from the Demographic and Health Surveys (DHS) in Ethiopia show that full immunization coverage among children aged 12-23 months increased from 14.3% in 2000 to 38.5% in 2016. However, factors contributing to the increment are poorly understood. This study aims to identify the driving factors behind the change in childhood immunization coverage in Ethiopia between 2000 and 2016.

METHODS: Data from two rounds of the Ethiopian DHS (2000 and 2016) were used. Oaxaca–Blinder decomposition analysis was used to identify the contribution of the underlining determinants to the change in full immunization coverage over time. The analysis partitioned the observed change in childhood immunization coverage into “explained” and “unexplained” parts. The “explained” part is due to differences in levels of determinants between the two time periods whereas the “unexplained” part arises due to the differential effect of the determinants and other factors not included in the model on full immunization coverage between the two time periods.

RESULTS:The decomposition analysis estimated that about 39% (p<0.001) of the overall change in immunization coverage was due to differences in the level of the determinants between 2000 and 2016. Decrement in the proportion of mothers with no education and increments in the levels of antenatal care utilization between the two time periods were significant sources of this change. The remaining 61% (p<0.001) of the change is attributed to the difference in the effect of determinants.

CONCLUSIONS:Several factors contributed to the change in childhood immunization coverage in Ethiopia. Further improvements in antenatal care utilization and maternal education can enhance the national immunization coverage. This study also highlight the need to understand how various factors affect immunization behavior in order to sustain the observed change.