Abstract
Healthy volunteers (HVs) who participate in clinical trials are a vulnerable group that deserves specific protection. We assessed the number and types of studies that involve HVs around the world and outline the methodological barriers to their analysis. We found that tens of thousands of HVs are involved every year in clinical trials in a large variety of countries and that the overwhelming majority of studies are not “first-in-human” but pharmacokinetic studies. The two cornerstones for both ethical and safe participation of HVs in clinical trials are properly obtained informed consent and a minimization of exposure to risk, in particular by avoiding concealed participation in multiple trials. To minimize the risk of exploitation of HVs and their exposure to risk, we propose ways to ensure genuine informed consent, and advocate setting up national healthy volunteer registries as established in France and the U.K.