Using the theoretical domains framework to explore reasons for missed opportunities for vaccination among children in Kano, Nigeria: a qualitative study in the pre-implementation phase of a collaborative quality improvement project.

: Missed opportunities for vaccination (MOV) have been identified as an important contributor to low childhood immunization coverage. In this study, we explore the reasons for MOV from the perspective of caregivers of children aged 0-23 months attending primary health care (PHC) facilities in Nassarawa Local Government Area (LGA) of Kano State, Nigeria. This was to inform the implementation of a quality improvement program to reduce MOV. : An exploratory qualitative research was conducted using focus group discussions (FGD) with caregivers of children aged 0-23 months that visited PHC facilities. The study was conducted in three purposively selected PHC facilities in Nassarawa, Kano. The caregivers were purposively selected from the three PHC facilities and were homogenous in terms of their place of residence. Each FGD was conducted face-to-face in a private room within the health facility. During the discussion, participants maintained a circular sitting arrangement. The FGD were audio-recorded, transcribed verbatim, and analyzed using template analysis approach through the lens of the theoretical domains framework (TDF) and the capability, opportunity, motivation - behavior (COM-B) model. The researchers that conducted this study are epidemiologists and implementation scientists with experience in immunization programs. They are multilingual, and some are fluent in both English and Hausa language. Although four of them are medical doctors, however, they do not have any affiliations or provide health services in any of the PHC facilities where this study was conducted. : Five FGD with 30 caregivers was conducted. The caregivers were aged between 19 and 32 years and lived within the LGA. Based on their lived experiences, several factors that are responsible for MOV were identified and categorized into three constructs based on the COM-B model. Capability encompassed caregiver's inadequate knowledge of the vaccines that children need. The opportunity included contextual factors such as non-screening of home-based records, health worker's refusal to offer immunization services, and husband's refusal due to socio-cultural beliefs. Finally, motivation included fear of the side effects of vaccination. : This study identified a useful framework that aided deeper insights into caregiver-related factors responsible for MOV in Nassarawa, Kano. Some of the findings from this study can be used to inform change ideas in a quality improvement program and should be explored.