Historically, vulnerable subjects were often enrolled as subjects, sometimes unwittingly, in research studies that were not relevant to their own conditions and that ultimately benefited the health of more privileged members of society. This is now viewed as unethical, and the enrollment of vulnerable subjects in research today is governed primarily by the ethical principles of justice and respect for persons.
The principle of justice requires that the vulnerable be extended special protections with regard to the distribution of the benefits and burdens of research. The vulnerable should be assured of receiving their fair share of the benefits and protected from having imposed upon them more than their fair share of the burdens of research. For example, certain categories of vulnerable subjects, such as prisoners, may be continually sought as research subjects in clinical drug trials because of their accessibility and willingness to accept risks in exchange for cash or privileges. Yet these individuals (prisoners) may not receive the benefits of the research if they are at low risk of being affected by the health condition the drug is intended to alleviate. Vulnerable subjects should not be considered for enrollment as subjects in research when the risk level is greater than minimal, the research is not relevant to their class of persons (e.g., prisoners), and the procedure or intervention does not hold out the prospect of direct benefit to the individual subject. Investigators enrolling vulnerable subjects in research studies that will exceed minimal risk must justify these risks and incorporate additional safeguards to ensure that the subjects are protected from harm.
Respect for persons is interpreted as requiring that investigators show respect for a potential subject’s capacity for self-determination to the extent that it exists. If the vulnerable subject has a reduced capacity to protect his or her own interests during the negotiation for informed consent, then special provisions must be included in the protocol to allow the subject to assent to participation (register knowledgeable agreements) and, whenever possible, supplement this with the permission of a legally authorized representative, such as a parent or legal guardian in the case of children.