Abstract:

The dropout rate is the proportion of vaccine recipients who have not completed their vaccination schedules. In The Gambia, vaccination dropout persists despite rising immunization coverage from 76% in 2013 to 85% in 2020. The 2020 DHS reports high initial uptake of multi-dose vaccines (98–99%), but final-dose completion drops to 92–95%. These disparities highlight systemic barriers and the need to identify determinants of dropout to guide targeted interventions. This study employed a mixed-methods approach, combining a quantitative unmatched case–control design with a qualitative component. In the quantitative phase, mothers of children who completed the routine immunization schedule (controls) compared with mothers of children who experienced vaccination dropout (cases). The qualitative component included in-depth interviews with mothers from both groups to explore contextual factors, perceptions, and lived experiences related to vaccination completion. The findings indicated that maternal education was consistently associated with vaccination dropout. Children from households in the poorest wealth quintile were more likely to drop out of routine immunization compared with those in the highest wealth quintile. Maternal age was also significantly associated with vaccination dropout. Geographic access played an important role: shorter distance to health facilities was associated with lower dropout rates, while limited access to nearby health services contributed to higher vaccination dropout. Identifying the factors associated with dropout is essential for designing targeted interventions. Strengthening community-based outreach, improving service accessibility, and promoting maternal health service use may help reduce dropout and enhance immunization outcomes.

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