Assessing the Willingness of Future Health Care Providers to Participate in Vaccine Trials: Cross-Sectional VACCELERATE European Study.

Background: Future health professionals are expected to recommend vaccines, communicate with patients about vaccine safety, and support clinical trial literacy and recruitment during public health emergencies. However, their own willingness to participate in vaccine trials, and the barriers that shape that willingness, remain incompletely characterized across Europe. Objective: This study aimed to assess willingness to participate in future vaccine trials among European students in health-related disciplines and to describe their perceived barriers, motivations, vaccine attitudes, and preferred sources of health information. Methods: We conducted an open, multilingual, cross-sectional web survey within the VACCELERATE network from June to November 2023. National coordinators distributed the survey through institutional mailing lists, student associations, and program channels in participating European countries. Eligible participants were students aged 18 years or older enrolled in medicine, dentistry, nursing, pharmacy, psychology, biomedical sciences, physiotherapy, occupational therapy, or other health-related programs. The questionnaire assessed demographic characteristics, primary sources of health information, vaccine attitudes, willingness to participate in future vaccine trials, barriers among unwilling or unsure respondents, and motivations for participation. Analyses were descriptive, and denominators varied by item because nonmandatory questions could be skipped. Results: Of 1381 eligible respondents, 1192 (86.3%) answered the primary willingness question: 32.9% (n=392) were willing to participate in a future vaccine trial, 38.8% (n=463) were unsure, and 28.3% (n=337) were unwilling. Among the 769 respondents who were unwilling or unsure and selected barriers, the most frequent concerns were potential side effects (n=574, 74.6%) and not wanting to be a "test subject" (n=276, 35.9%). Among 1289 respondents included in the motivation analysis, commonly selected motivators included knowing the risks and side effects involved (n=575, 44.6%), becoming part of the solution to an important health problem (n=584, 45.3%), and knowing that personal safety would be protected (n=500, 38.8%). Conclusions: In this multicountry European sample of health professional students, only one-third reported willingness to participate in future vaccine trials, while the largest group was unsure. The findings suggest that trial-readiness initiatives for future health professionals should prioritize transparent communication about safety monitoring, risks and side effects, participant protections, and the practical conduct of vaccine trials. Because recruitment used an open convenience approach, the results should be interpreted as exploratory and hypothesis generating rather than representative of all European health professional students.