Factors Associated with the Change in Childhood Immunization Uptake in Nigeria: A Decomposition Analysis

Abstract

Childhood immunization increased from 23% in 2008 to 31% in Nigeria. However, the factors that contributed to the change have not been systematically investigated. Using diphtheria, pertussis, and tetanus (DPT) as a measure of immunization, this study investigated the factors that account for the change in the proportion of children aged 12-23 months who received complete DPT vaccination between 2008 and 2018. Data were obtained from the Nigeria Demographic and Health Surveys of 2008 and 2018. The decomposition logit model was used to analyze data of 7,356 children aged 12-23 months. There was an increase in complete DPT-uptake from 36% in 2008 to 55% in 2018. The increase was mainly due to a change in behaviour toward immunization as 54.2% of the total change was explained by the coefficient effect of the selected explanatory variables. The independent variables that contributed significantly to the increase in DPT immunization were region, education, place of delivery, marital status, work status, needing permission to visit a health facility, religion, household wealth, birth weight, exposure to the media, and mother’s age. Nigeria must prioritize attention to factors that account for positive change in vaccination if the country would achieve the 2030 global immunization agenda to halve the number of zero-dose children and 90% coverage, with at least 80% coverage in each State of Nigeria.