Abstract
Background: Childhood vaccination remains the cornerstone of public health strategies, substantially reducing global morbidity and mortality, yet suboptimal uptake persists in many settings. In South Africa, the challenge is evident, with persistent outbreaks of vaccine-preventable diseases. Addressing localised immunisation shortfalls requires elucidating the complex interplay of factors beyond conventional access barriers. This qualitative study provides context-specific insights into the behavioural and social drivers influencing childhood vaccination uptake among caregivers in Cape Town, South Africa. Methods: Utilising an exploratory qualitative research design, thematic analysis was applied to interview data (n = 25 caregivers) collected via a purposive sampling strategy designed to capture maximum variation in experiences within targeted low-uptake subdistricts. Interpretation of the data was systematically guided by the World Health Organization's Behavioural and Social Drivers (BeSD) framework. The latter consists of four domains, namely, "Thinking and Feeling", "Social Processes", "Motivation", and "Practical Factors". Findings: Analysis across BeSD domains reflected a pattern of the intention-behaviour gap, where caregivers are motivated for vaccination but face structural and practical barriers affecting timely uptake. In the Thinking and Feeling domain, widespread conviction regarding the vital benefits of vaccination co-existed with significant anxiety concerning minor side effects (e.g., pain and fever), which sometimes precipitated missed subsequent appointments. Caregivers frequently accept immunisation as a social routine despite having limited knowledge of the diseases it prevents. Social Processes demonstrated that while decision-making authority rested primarily with mothers, compliance relied on the delegation of logistical responsibilities to extended family members. Critically, reports of poor communication, judgment, or negative attitudes among healthcare workers undermined trust and acted as barriers to sustained engagement. Within the Practical Factors domain, structural constraints frequently overshadowed high intent, with pervasive issues such as long waiting times and financial costs cited as the main reasons for missed appointments. Conclusions: Participants generally expressed strong acceptance of vaccination, but attainment of optimal coverage is constrained by systemic failures in patient-provider communication and persistent logistical barriers within the public healthcare delivery system. Strategic public health interventions must therefore move beyond addressing only attitudinal opposition to prioritise targeted efforts that mitigate structural constraints and reinforce personalised, empathetic communication to sustain caregiver confidence and adherence.