Parental motivations, facilitators, and barriers to participating in a pediatric vaccine trial in Kathmandu, Nepal: A qualitative study.

Pediatric vaccine trials are essential for generating evidence to inform immunization policy, yet their success depends on effective recruitment and sustained participation of children and their caregivers. Understanding parental decision-making is particularly important in low- and middle-income countries, where sociocultural dynamics, trust, and access to healthcare may shape willingness to participate in research. This qualitative study explored parental motivations, facilitators, and barriers to participation in a pediatric vaccine clinical trial conducted in Kathmandu Valley, Nepal. Semi-structured interviews were conducted with 33 parents whose children were enrolled in the OptImms trial, a randomized study evaluating alternative diphtheria, tetanus, and pertussis (DTwP) immunization schedules. Interviews were conducted in Nepali, transcribed, translated, and analyzed thematically. Trust in healthcare workers, research institutions, and scientific processes emerged as a central facilitator of participation. Social dynamics, including joint decision-making within families and reassurance from relatives working in healthcare, strongly influenced enrollment decisions. Practical facilitators, such as efficient scheduling, access to additional healthcare, and reimbursement for travel costs, further supported participation. Barriers included time constraints, geographical distance, and concerns about invasive procedures, such as blood sampling. These findings highlight the importance of trust-building, culturally sensitive communication, and logistical support in the ethical design and implementation of pediatric vaccine trials. Addressing these factors may improve recruitment and retention in future vaccine trials in Nepal and similar settings.