Group questions value of vulnerability designation

Concept has lost meaning over time

Although IRBs are often charged with giving special consideration to research involving subjects deemed to be particularly vulnerable to exploitation, there is no standard definition of what this term means, and no guidance governing what additional protective measures it should prompt.

Moreover, argues a group of research ethicists, so many people and groups of people are now considered to be vulnerable that the concept itself has lost meaning and needs to be re-examined.

"When we talk about vulnerability now, we tend to focus exclusively on the capacity to give informed consent," says Carol Leavine, director of the Families and Health Care Project at the United Health Fund of New York and a member of the national Consortium to Examine Research Ethics. The consortium recently published a report detailing the limits on the concept of vulnerable populations. "But then, many IRBs don’t take that a step further and ask themselves, in what ways does the research protocol pose special risks to this group of people, or to anyone, and are these risks acceptable? They tend to focus on making sure that there is informed consent, and then deciding if that exists, then it’s OK."

Since the now commonly accepted codes of research ethics were developed in the mid and late 1970s, the research enterprise has changed dramatically, the group points out. Where the Belmont Report focused on protecting certain specifically defined populations, such as children, the mentally ill, or persons confined to institutions, many more groups of people are now considered to be at least potentially vulnerable. For example, the concept of vulnerability has grown to include whole societies of Third World countries in which the United States and other industrialized countries want to conduct studies.

Almost everyone, at some point, due to some facet of their life or work, could be considered a member of a vulnerable group, Leavine says.

Aside from subjects in need of the special protections clearly defined in the law — children, prisoners, etc. — categorizing a subject as vulnerable can have a stigmatizing and limiting effect.

"Not all members of potentially vulnerable populations will be vulnerable in the same way," Leavine says. "One person’s ability to understand the risks and benefit of a particular protocol and willingness to consent may be very different than his neighbor’s, though they both may be considered members of a vulnerable population."

In some cases, focusing on the population as vulnerable masks larger problems with the research protocol and with society.

"For example, there is a lot of concern that poor people might be unduly coerced to participate in medical research as a means of getting access to basic medical care," she notes. "While this is certainly valid, we should address the problem of people not being able to afford health care, rather than just considering it one of a number of factors that might make this person a bad candidate for research."

Some people may be at higher risk for harm from certain aspects of a particular protocol, even though they may not objectively be considered a member of a vulnerable population, she adds. People with a rare genetic disease might be more vulnerable to risk and coercion in a study of an experimental therapy, for example.

The group advocates an approach that focuses more on the risks posed by individual protocols, evaluating these to determine whether they place specific groups, or all potential subjects, at increased risk for harm — and determine ways in which investigators should minimize the risk and seek appropriate informed consent.

Certain studies, they say, should be categorized as requiring special scrutiny by IRBs.

A study would require special scrutiny if one of the three criteria are met:

  • the research involves initial experiences of translating scientific advances into humans, especially when the intervention is novel and/ or irreversible;
  • there is known or credible risk of significant harm and there is no potential of an offsetting direct medical benefit;
  • the protocol raises ethical questions about research design or implementation to which there is no consensus.

Special scrutiny is a mechanism that aims to provide appropriate protections to all research participants, not just those officially deemed vulnerable, Leavine says.

"Some have interpreted our argument to mean that we want to abandon the concept of vulnerability completely and not consider special protections for certain groups of people," Leavine says. "That is not the case at all. We certainly respect the need for certain protections — those for children, as we mention, and there should be clearer regulations governing research among the mentally ill and those with diminished mental capacity. But we also want to urge IRBs to also consider the ways that people are individually vulnerable. What characteristics of each protocol might make certain people more vulnerable."


1. Levine C, Faden R, Grady C, et al. The limitations of vulnerability as a protection for human research participants. Am J Bioethics 2004; 4:44-49.