Trends in vaccination coverage and equity in the Democratic Republic of the Congo from 2017 to 2023

Several routine immunization (RI) strengthening efforts have been implemented in the Democratic Republic of the Congo (DRC) in the last decade. However, there has been no assessment of national or provincial-level trends in inequalities in RI coverage since the implementation of these programs. In this analysis, we aimed to describe trends in childhood vaccination coverage and inequalities from 2017 to 2023 at the national and provincial levels and to compare these trends among groups of provinces where two initiatives have been in place: the Mashako plan and a provincial level public-private partnership using a memorandum of understanding (MOU) approach.

We used population-based surveys including the Multiple Indicator Cluster Survey (MICS) - Palu 2017-2018 survey and four annual vaccination coverage surveys conducted from 2020 through 2023. We described vaccination coverage (three doses of pentavalent vaccine (Penta3) and at least one dose of a measles containing vaccine (MCV1)) and assessed relative and absolute inequalities in vaccination coverage by maternal education and household wealth at each time point. Analyses were conducted at the national level and within two groups of provinces: those initially included in the Mashako plan in 2018 and those initially included in the MOU approach. Inequality estimates were pooled across province groups using a random effects DerSimonian and Laird estimator for meta-analysis.

From 2017 to 2023, national Penta3 coverage increased by 9.9 percentage points (47.7 % to 57.6 %) while MCV1 declined by 6.7 percentage points (58.9 % to 52.2 %). As of 2023, substantial wealth and education-related inequalities in childhood vaccination coverage remained: at the national level, children from wealthier households were 2.23 times more likely to receive Penta3 compared to children from poorest households (95 % Confidence Interval (CI) 2.16-2.31). Between 2017 and 2023, absolute and relative wealth-related inequalities appear to have declined, but differences were not statistically significant. Education-related inequalities have improved less than wealth-related inequalities. Though differences were often not statistically significant, reductions in inequalities were generally larger in provinces initially included in the Mashako plan and the MOU approach than in provinces not initially included in either initiative. Initial improvements in coverage and inequality between 2017 and 2020-2021 have largely stagnated at the national and sub-national levels in 2022 and 2023.

Efforts remain needed to reach RI coverage and equity targets in the DRC. Routine monitoring of inequalities in RI coverage should be performed regularly to track progress. A more explicit equity focus in RI strengthening initiatives in the DRC may be necessary to accelerate progress in reducing existing inequalities.