Money-oriented risk-takers or deliberate decision-makers: a cross-sectional survey study of participants in controlled human infection trials

OBJECTIVE: To quantitatively investigate the motivations, decision-making and experience of participants in controlled human infection (CHI) studies. DESIGN: Cross-sectional descriptive survey study. SETTING: Previous participants of CHI studies at the Leiden Controlled Human Infection Center, control group of students from Leiden University. PARTICIPANTS: 61 previous participants and 156 controls. MEASUREMENTS: Ranking of motivational and decisional factors, risk propensity score and multiple-choice questions on experience of trial participation and ethical aspects of CHI studies. RESULTS: Motivating factors for participants were contributing to science (81%), contributing to research that may benefit developing countries (72%) and the financial compensation (63%). For 51% of participants, a reason other than financial compensation was the most important motivational factor. Participants considered trust in the study team (70%), time investment (63%), severity of symptoms (54%), chance of developing symptoms (54%) and whether it is an easy way to make money (54%) in their decision to participate. Most CHI participants (84%) were proud of their participation, would advise others to participate (89%) and would participate in a similar trial again (85%). CHI participants had a higher risk propensity score than students (estimated difference 0.9, p<0.001). CONCLUSION: Although financial compensation is important, the motivations for participants in a CHI study are diverse and participants make a balanced appraisal of risks and burden before participating.