BACKGROUND: Routine childhood immunization in the Central African Republic (CAR) is inconsistent due to reasons including political instability and service disruptions. This study assessed dropout between the first and third pentavalent doses among children aged 12-23 months who had received Penta 1, identified associated risk factors, and explored caregiver-reported barriers. Additional dropout indicators within this cohort-specifically from Penta 1 to Penta2, from Penta2 to Penta 3, and from Penta 3 to measles-were also examined to support contextual interpretation. METHODS: We conducted a cross-sectional household survey from December 2023 to March 2024, based on a nationally representative sample covering all seven health regions and 35 districts of the CAR. This secondary analysis focused on dropout between key vaccine doses among children aged 12-23 months and was conducted using Stata 17. Data were collected through structured interviews with caregivers, with vaccination status primarily verified using home-based records; when unavailable, health facility data or caregiver recall were used. Survey-weighted logistic regression models were used to identify factors associated with vaccine dropout. Reasons for non-vaccination were analyzed thematically using the adapted WHO BeSD framework. RESULTS: Among 4121 children aged 12-23 months who had received Penta 1, the national prevalence of dropout between the first and third doses of the pentavalent vaccine was 34.5% (95% CI: 32.4-36.6). Additionally, among these children, we observed 17.0% dropout from Penta 1 to Penta2, 17.5% from Penta2 to Penta 3, and 15.8% from Penta 3 to the measles-containing vaccine. Higher odds of dropout between Penta 1 and Penta 3 were associated with households lacking television (aOR: 2.98; 95% CI:1.88-4.72), absence of birth registration (aOR:1.56; 95% CI:1.26-1.94) and caregivers engaged in agricultural activities (aOR:3.45; 95% CI:1.85-6.44). Primary reported reasons for non-vaccination included access barriers such as distance to the vaccination site (30.9%) and vaccine stockouts (14.0%), contextual and household challenges like caregiver time constraints (29.7%) and family-related problems (10.8%), information gaps including lack of knowledge about the vaccination schedule (27.3%), and motivational concerns such as fear of side effects (10.4%) and distrust in vaccines (2.9%). CONCLUSION: In the CAR, 34.5% of children who receive the first pentavalent dose fail to complete the three dose vaccination series. Improving follow-up and adapting services to overcome local barriers is essential to increase rates of complete immunization.
Ishoso et al. (Fri,) studied this question.