INTRODUCTION: The role of healthcare providers and their use of systems is one of the most important factors in vaccination uptake.

AIM: To identify reasons and find patterns behind why immunisation providers code the word decline in their system for childhood immunisation events.

METHODS: A qualitative study involving face-to-face semi-structured interviews with staff members involved in immunisation delivery. General practices were purposively selected for having either high or low rates of registered children coded on the electronic practice management system as having declined immunisation events. Thematic analysis was undertaken using an inductive approach to link themes to the data.

RESULTS: A total of 35 interviews were conducted with practice nurses; 21 were from practices wit high rates of registered children recorded as having declining immunisation events, and 14 practices with low rates of declining. Common themes were: effective use of systems, early and ongoing engagement, adequate health care practitioner time and practitioner experience. Practices with low rates of coded decliners had stronger approaches for early and ongoing engagement, and were less likely to use formalised decline forms. As practiceimmunisation coverage rates improved over time, there was perceived to be less expressed vaccine hesitancy from families.

CONCLUSIONS: The reasons for coding individuals as ‘decliners’ are a complex mixture of individual, community, practitioner and practice systems. Front-line providers need adequate tools, time and resourcing to support effective and ongoing engagement with families. Community factors have influence but can change over time.

KEYWORDS: Immunisation, Immunisation coverage, Primary care, Systems