Changes in immunization coverage and contributing factors among children aged 12–23 months from 2000 to 2019, Ethiopia: Multivariate decomposition analysis

BACKGROUND: Immunization has been promoted as a global strategy aimed at improving child survival. The World Health Organization strives to make immunization services available to everyone, everywhere to save over 50 million lives by 2030. Monitoring the change and identifying the factors contributing to the change in immunization coverage over time and across the nations is imperative for continuing global success in increasing immunization coverage. In this study, we examined the changes and factors that contributed to the change in full immunization coverage over time in Ethiopia (2000 to 2019). METHODS: We analyzed data on children aged 12–23 months, extracted from the 2000 and 2019 Ethiopian Demographic and Health Survey (EDHS) datasets. A total of 3,072 weighted samples (2,076 in 2000 and 966 in 2019) were included in the analysis. A multivariate decomposition analysis technique was used to determine change and identify factors that contributed to the change over time. Statistical significance was defined at a 95% confidence interval with a p-value of less than 0.05. RESULTS: There was a 29.56% (95% CI: 24.84, 34.28) change in full immunization coverage between the two surveys. It increased from 14.62% (95% CI: 12.43, 17.11) in 2000 to 44.18% (95% CI: 37.19, 51.41) in 2019. The decomposition analysis showed that about 75% of explained change was attributed to the differences in the composition of explanatory variables (the endowment effect). Particularly, women aged 35–49 years (-2.11%), those who attended four or more antenatal care visits (17.06%), individual who had postnatal care visits (16.90%), households with two or more under-five children (2.50%), and those with a history of child mortality (17.80%) were significantly attributed to the change. The rest, 25% of the explained change was attributed to the difference in the effects of explanatory variables (coefficient). The change in the coefficient for women who had experienced child death (-20.40%) was statistically significant to the change in full immunization coverage over time. CONCLUSION: The finding of this study revealed that there was a statistically significant change in full immunization coverage over time. The majority of the change was attributed to the differences in the composition of explanatory variables such as antenatal care and postnatal care visits, age of the mother, and number of living children in the household. Therefore, strengthening maternal health services utilization may enhance immunization coverage in Ethiopia. Furthermore, the difference in coefficient of mothers with a history of child death had a substantial counteracting effect on the change, emphasizing the importance of raising awareness and delivering vaccine education to them and the larger community.