High immunisation coverage but sporadic outbreaks of vaccine-preventable diseases: the structural gaps in vaccination uptake in central highlands, Vietnam.

Background: Despite the successful implementation of the Expanded Programme on Immunization (EPI) for the past three decades, Vietnam has recently witnessed outbreaks of vaccine-preventable diseases, indicating a potential gap in immunisation uptake across population groups. Daklak province is a rural highland area, home to 46 ethnic groups with complicated socio-economic backgrounds. The province reported sporadic outbreaks of vaccine-preventable diseases and low vaccine uptake in some remote low-socioeconomic groups despite a high record of provincial coverage. Within this context, we aim to explore the perspectives and experiences of ethnic minority communities related to EPI vaccination and how socio-economic and contextual factors influence such views and practices in Daklak province.

Methods: We used qualitative data collected between 2018 and 2022 from in-depth interviews, focus group discussions, and participant observation with different stakeholders of the EPI programme. The study took place in nine districts across 25 communes of the province with different socio-economic characteristics and vaccination patterns. We invited mothers who were the primary caregivers taking children to vaccination and healthcare workers who were directly involved in vaccination delivery in the local areas. We incorporated the SAGE's public health framework of the vaccine hesitancy matrix and the anthropological concept of structural vulnerability to discern the structural roots of vaccine attitudes and behaviours of the community.

Results: Overall, the research shows that views and behaviours related to children's vaccination are complicatedly influenced by multi-ecological factors. In particular, we found a critical influence of socioeconomic conditions and social networks on the community's vaccine acceptance and uptake. The community's interaction with the health system and the government through local healthcare workers was also critical in fostering community trust towards vaccines and the EPI programme. In addition, we revealed that the issues with non-compliance to the EPI in the lowest-uptake communities were structurally related to their economic vulnerabilities and social marginalisation.

Conclusions: These findings implicate the need for tailoring public health and socioeconomic interventions to enhance vaccination opportunities in the marginalised groups.