The genetically attenuated malaria vaccine PfSPZ-GA1 is safe, immunogenic, and has suboptimal protective efficacy in people.

Schistosomiasis is an infection caused by contact with Schistosoma -contaminated water and affects more than 230 million people worldwide with varying morbidity. The roles of T helper 2 (T _H 2) cells and regulatory immune responses in chronic infection are well documented, but less is known about human immune responses during acute infection. Here, we comprehensively map immune responses during controlled human Schistosoma mansoni infection using male or female cercariae. Immune responses to male or female parasite single-sex infection were comparable. An early T _H 1-biased inflammatory response was observed at week 4 after infection, which was particularly apparent in individuals experiencing symptoms of acute schistosomiasis. By week 8 after infection, inflammatory responses were followed by an expansion of T _H 2 and regulatory cell subsets. This study demonstrates the shift from T _H 1 to both T _H 2 and regulatory responses, typical of chronic schistosomiasis, in the absence of egg production and provides immunological insight into the clinical manifestations of acute schistosomiasis.

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.