Investigators, in conjunction with their local Institutional Review Boards (IRBs), are responsible for protecting the rights and welfare of human research subjects. IRBs and investigators must pay special attention to studies involving certain categories of people, termed vulnerable subjects. Vulnerability with regard to research is understood as a condition of individuals, either intrinsic (e.g., being a child) or situational (e.g., being inebriated), that may interfere with their autonomy or decision-making capacity. In general, persons are vulnerable in research either because they have difficulty providing informed consent (understanding and protecting their own interest) or because their circumstances may subject them to intimidation and exploitation (e.g., they may feel compelled to participate for economic reasons or for fear of loss of health care or other services). According to the Common Rule (a federal regulation governing the involvement of human subjects in research), investigators should be particularly cognizant of the special problems of involving vulnerable populations, such as children, prisoners, mentally disabled persons, and economically or educationally disadvantaged persons, in research. The Common Rule contains specific information that governs the involvement of some (but not all) of these special populations in research.
The populations described in the Common Rule should not be considered to be the only categories of vulnerable subjects. Other unlisted populations, such as students, the seriously ill, and those individuals with substance abuse problems, may also be vulnerable in certain situations. Each investigator must thoughtfully evaluate the ability of their intended subjects to independently enter into an informed-consent agreement and protect their own interests throughout the study. If subjects are vulnerable (or may become vulnerable during the study), investigators must follow the federal regulations or their IRB’s policies and procedures, which may impose stricter informed-consent requirements and place limits on the level of risk to which these subjects may be exposed.