Development and psychometric testing of a parental knowledge, attitude, and practices questionnaire on pentavalent vaccine safety

Background and objectives Pentavalent vaccine safety awareness significantly influences parental acceptance, yet evidence-based knowledge, attitudes, and practices related to adverse events following pentavalent vaccination remain underexplored. This study aimed to develop and psychometrically validate the knowledge, attitude, and practices on pentavalent vaccine safety questionnaire to assess parental perspectives on pentavalent vaccine safety. Methods A sequential mixed-methods psychometric validation study was conducted in three stages: instrument development, pilot testing, and large-scale psychometric evaluation. Healthcare professionals were purposively sampled, while parents or caregivers of infants scheduled for pentavalent vaccination in rural Karnataka, South India, were selected via convenience sampling (pilot) and stratified random sampling (large-scale). Results An initial 50-item close-ended questionnaire, covering knowledge, attitude, and practice domains, was drafted through literature review and refined by an expert panel. Content validity was confirmed with content validity ratio ≥0.6 and content validity index ≥0.8, resulting in 34 retained and 16 revised items. Pilot testing in 24 rural parents and validation in 321 rural parents demonstrated acceptable internal consistency (Cronbach’s alpha ≥0.7) and test-retest reliability (intraclass correlation coefficient ≥0.8). Discriminant validity was observed with significantly higher practice score differences for parents with prior adverse immunisation events exposure (n=24). Exploratory factor analysis of 11 thematic domains identified three factors explaining 43.9% of total variance, confirming construct validity. Interpretation and conclusion The knowledge, attitude, and practices on pentavalent vaccine safety questionnaire is a valid and reliable tool identifying gaps in parental knowledge, attitude and practice related to awareness and reporting of pentavalent vaccine safety, supporting improved monitoring and public trust.