Factors associated with vaccine default in Southern Ghana based on data from the RTSS malaria vaccine trial in Cape Coast

Malaria has been a severe global and public health concern for the last couple of decades. Ghana, like many other countries in sub-Saharan Africa, is most affected by the disease, with children facing dire consequences. The recent introduction of the RTS, S malaria vaccine holds great potential in reducing malaria fatalities in children. However, RTS, S implementation have inherent challenges that raise the stakes of vaccine defaults in piloted areas in Ghana. In this study, we examine the predictors of RTS, S vaccine defaults using a cross-sectional research design that covers a sample of 765 caregivers in Southern Ghana. Classification models (Binary logistic regression and Random Forest) were performed to identify critical socio-demographic, health and RTS, S related predictors. The findings show that more than a third (38.43%) of children defaulted at least one dose of the malaria vaccine. Key predictors of defaults included sub-metro of residence, cost of traveling to health facilities, experience of adverse events, knowledge about the vaccine doses, caregiver's employment status, and religion. Our findings emphasize the need for targeted interventions to reduce defaults, mainly focusing on caregiver education on vaccines, reducing financial barriers to healthcare access, and addressing concerns about adverse events.