Factors influencing participation in controlled human infection models: a pooled analysis from six enteric fever studies

Abstract

<ns4:p><ns4:bold>Background:</ns4:bold> Enteric fever is an acute febrile-illness caused by infection with the human-restricted <ns4:italic>Salmonella</ns4:italic> serovars Typhi and Paratyphi. Controlled human infection models (CHIM) of <ns4:italic>S</ns4:italic>. Typhi and Paratyphi infection are used to accelerate vaccine development and to better understand host-pathogen interactions. The primary motivations for participants to take part in these studies are unknown. We studied participant motivations, attitudes and the factors influencing CHIM study participation.</ns4:p><ns4:p> <ns4:bold>Methods:</ns4:bold> Participant surveys were nested in six enteric fever CHIM studies conducted at a single centre in Oxford, UK, between 2011 and 2017. All eligible participants received one invitation to complete an anonymous, self-administered paper or online survey on either day 28 or 60 after challenge. A descriptive analysis was performed on these pooled data. All studies were included, to minimize selection bias.</ns4:p><ns4:p> <ns4:bold>Results:</ns4:bold> Survey response rates varied from 33.0%-86.1%, yielding 201 participants. In the cohort, 113/198(57.0%) were educated to bachelor’s level, 61.6% were employed, 30.3% were students and 4.6% were unemployed. The most commonly cited motivations for CHIM study participation were a desire to contribute to the progression of medicine (170/201; 84.6%); the prospect of financial reimbursement (166/201; 82.6%) and curiosity about clinical trials (117/201; 57.2%). The majority of respondents (139/197; 70.6%) reported that most people advised them against participation.</ns4:p><ns4:p> <ns4:bold>Conclusion:</ns4:bold> Motivation to participate in a CHIM study was multi-factorial and heavily influenced by internal drivers beyond monetary reimbursement alone. High educational attainment and employment may be protective factors against financial inducement; however, further research is needed, particularly with CHIM studies expanding to low-income and middle-income countries.</ns4:p>