We examined the experiences of participants in two S. pyogenes pharyngitis human challenge trials: 1) the CHIVAS-M75 dose-finding trial to establish the model, and 2) the CHIPS trial, using the model to determine the minimum penicillin concentration to prevent pharyngitis. Both studies included an inpatient admission of approximately 5 days and 1-6 months of periodic outpatient follow-up.
Data were collected by surveying 14 CHIVAS-M75 participants retrospectively and 60 CHIPS participants during the trial. Statistical and thematic analyses identified motivations, challenges, and perceived benefits of participation.
Financial remuneration was the primary motivation for most participants. CHIVAS-M75 participants recalled their experience as generally favourable, similar to other clinical trials, although one regretted participating. CHIPS participants anticipated moderate discomfort generally, with the experience of participation reported as worse than expected for 23 of 60 participants (38%). In CHIPS, anticipation and novelty initially kept participants engaged despite ongoing discomfort. Although participants with pharyngitis looked forward to recovering, most expressed satisfaction at having participated. Most participants (43, 72%) indicated their remuneration was ‘reasonable’ and 63% (38/60) indicated that they would participate in another human challenge trial. Participants largely remained motivated to contribute to research and were glad to gain insights into clinical research.
Future streptococcal pharyngitis human challenge research will be enhanced by ensuring participants fully understand the requirements and potential burdens of participation, and are kept as comfortable as possible during their inpatient stay. Involving participants in co-development of recruitment materials may facilitate recruitment and improve the participation experience in future trials.