Evolution of Factors Associated With Zero-Dose Status in Children Aged 12–23 Months in Mai-Ndombe Province, Democratic Republic Of Congo, 2021–2023: A Secondary Analysis of Vaccination Coverage Surveys

Abstract

Background: A "zero-dose" child is defined by the World Health Organization (WHO) as a child who had received no dose of the pentavalent vaccine, as determined from the vaccination card or caregiver recall. This study aimed to identify factors associated with zero-dose status among children aged 12–23 months in Mai-Ndombe Province between 2021 and 2023.

Methods: This was a secondary analysis of data from vaccination coverage surveys conducted in 2021, 2022, and 2023 by the Kinshasa School of Public Health. Household characteristics were analyzed using frequencies and percentages for categorical variables and means and standard deviations for continuous variables. A multivariate logistic regression model was used to identify factors associated with zero-dose status, reporting adjusted odds ratios (AORs) with 95% confidence intervals.

Results: The prevalence of zero-dose children dropped from 56.2% in 2021 to 22.4% in 2022, before rising again to 29.0% in 2023—still below 2021 levels. In 2021, the highest prevalence was observed among children from very poor households and mothers with no education, with religion also playing a role. In 2022, socioeconomic status, maternal age, and marital status were statistically significant. By 2023, maternal age, occupation, and marital status remained influential, although household wealth was no longer significant. Multivariate analysis confirmed these patterns.

Conclusion: Sociodemographic and economic factors particularly maternal characteristics play a key role in zero-dose prevalence. Tailored, community-sensitive strategies are needed to improve vaccination coverage.