The European Union's directive for clinical trials does not include explanations for or the reasoning behind the designation of certain groups as vulnerable. Although the inability to provide consent personally was a factor associated with vulnerability, arbitrary criteria may have been considered when classifying the populations of clinical trials as vulnerable. The EU Clinical Trials Register should provide guidance regarding exactly what aspects or factors should be taken into account to frame given populations as vulnerable, because vulnerability is not applicable to all risk situations. According to the guidelines of the International Conference on Harmonization (ICH), when the participant is not capable of providing informed consent—as in the case of illiterate patients—it is necessary for a legally accepted representative to participate in the process and provide this consent. In poor regions, however, the children—or even the adults—have difficulty in finding a legal representative. In these cases, the local ethics committee must decide how the consent is to be obtained. Emerging economies from lower middle-income countries have, in recent years, had the largest average annual growth rate, as well as increase, in number of clinical trials registered in the US government's database.
Nevertheless, careful supervision of research activities has to be ensured. Vulnerable populations need to be informed, educated, and protected from risks and damages. Public health laws and regulations need to be established and enforced. Infrastructure needs to be in place to detect early and reduce the impact of emergencies and disasters on health. Participating in research is definitely safer than high-risk occupations such as firefighting, law enforcement, or military service and almost certainly safer than the majority of construction work, manufacturing jobs, or garbage collection--jobs that are important and legitimate despite known risks. Like these occupations, clinical research produces a valuable social good that justifies placing individuals at some level of risk. All this action needs to be implemented through a public health system that is transparent and accountable. Governments in developing countries generally recognize that these public health functions are important, but they often lack the capacity and financial resources to implement them. Indeed, few low-income countries receive support for the core public health functions that should serve as the backbone of any well-functioning and sustained health system, including collection and dissemination of evidence for health policies, prevention and control of diseases, human resource development, and intersectoral action for better health.
Subjects with cognitive impairment are vulnerable to coercion, as they may have difficulty in making decisions based on evaluation of the possible risks and benefits of the study. Besides people with serious or potentially disabling or life-threatening conditions, others at risk of vulnerability are people living in nursing homes, recipients of welfare payments or social assistance, people in lower income brackets, the unemployed, patients in urgent or emergency care units, certain ethnic or racial minority groups, the homeless, members of nomadic communities, refugees, people displaced by conflicts or natural disasters, the incarcerated, the incurably ill, individuals from communities which lack political representation, and members of groups which are unfamiliar with the concepts of modern medicine. Children's participation as research subjects is only permitted if the scientific data to be obtained makes this absolutely necessary. Besides the consent of any child considered able to provide this, researchers must also obtain consent from parents or legal guardians. Moreover, authorized committees to which research proposals are submitted must include pediatricians. Countries from regions of Asia, Africa and Latin America may not have the habit of registering clinical trials in a European database. This may, therefore, impact on the results found in the present study, because other studies undertaken in Asia, Africa and Latin America may not be taken into account in the analysis, as only studies from the European register were analyzed.
Clinical trials registration is related to limitations such as poor quality of registered trial data; many clinical trials on the registers are incomplete, inaccurate, out-of-date or registered retrospectively. The ethical issues in involving the vulnerable population for research are still debatable. The justification for involving the vulnerable population in research is mainly when a particular problem affects that group. However, it is important to understand that participation in biomedical research not only poses risks, but also may provide benefit to participants and society.
