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Research with Vulnerable Populations

What is a vulnerable population?

In accordance with federal regulations, The University of Tennessee, Knoxville ensures that additional safeguards are included in the research design to protect participants that are likely to be vulnerable to coercion or undue influence or have diminished decision-making capacity.

There are specific subparts in the federal regulations that outline additional protections for pregnant women, prisoners, and children participating in research. However, other populations (such as students, employees, illegal immigrants, etc.) may also be considered vulnerable by nature of their age or mental, physical, economic, educational, or other circumstances.


For more information, contact the HRPP office at 

Please note that gaining approval for research involving vulnerable populations may take additional time. The HRPP recommends contacting us with any questions you have prior to submitting your application, and giving yourself plenty of time to gain approval.


In general, any risk present in research involving pregnant women, human fetuses, and neonates should be the least possible risk for achieving the objectives of the research.

Where scientifically appropriate, preclinical studies, including studies on pregnant animals, and clinical studies, including studies on nonpregnant women, should be conducted before pregnant women are involved in research so that researchers have data for assessing potential risks to pregnant women and fetuses.

Regarding the assessment of risk to pregnant women and fetuses in research, the risk to the fetus should be caused solely by interventions or procedures that hold out the prospect of direct benefit for the woman or the fetus; or, if there is no such prospect of benefit, the risk to the fetus should not be greater than minimal and the purpose of the research should be the development of important biomedical knowledge which cannot be obtained by any other means.

For the purposes of the federal regulations for human subjects research, prisoner means any individual involuntarily confined or detained in a penal institution. The term is intended to encompass individuals sentenced to such an institution under a criminal or civil statute, individuals detained in other facilities by virtue of statutes or commitment procedures that provide alternatives to criminal prosecution or incarceration in a penal institution, and individuals detained pending arraignment, trial, or sentencing.​​​​​​​

Note: these regulations do not apply to research aimed at a broader population that only incidentally includes prisoners.

Research with prisoners must fit into one of four categories:

(i) Study of the possible causes, effects, and processes of incarceration, and of criminal behavior, provided that the study presents no more than minimal risk and no more than inconvenience to the subjects;

(ii) Study of prisons as institutional structures or of prisoners as incarcerated persons, provided that the study presents no more than minimal risk and no more than inconvenience to the subjects;

(iii) Research on conditions particularly affecting prisoners as a class (for example, vaccine trials and other research on hepatitis which is much more prevalent in prisons than elsewhere; and research on social and psychological problems such as alcoholism, drug addiction, and sexual assaults).

(iv) Research on practices, both innovative and accepted, which have the intent and reasonable probability of improving the health or well-being of the subject.

In addition, the following additional protections apply to research with prisoners:

  • Any possible advantages accruing to the prisoner through his or her participation in the research, when compared to the general living conditions, medical care, quality of food, amenities and opportunity for earnings in the prison, are not of such a magnitude that his or her ability to weigh the risks of the research against the value of such advantages in the limited choice environment of the prison is impaired;
  • The risks involved in the research are commensurate with risks that would be accepted by nonprisoner volunteers;
  • Procedures for the selection of subjects within the prison are fair to all prisoners and immune from arbitrary intervention by prison authorities or prisoners. Unless the principal investigator provides to the Board justification in writing for following some other procedures, control subjects must be selected randomly from the group of available prisoners who meet the characteristics needed for that particular research project;
  • The information is presented in language which is understandable to the subject population;
  • Adequate assurance exists that parole boards will not take into account a prisoner’s participation in the research in making decisions regarding parole, and each prisoner is clearly informed in advance that participation in the research will have no effect on his or her parole; and
  • Where the Board finds there may be a need for follow-up examination or care of participants after the end of their participation, adequate provision has been made for such examination or care, taking into account the varying lengths of individual prisoners’ sentences, and for informing participants of this fact.

Research with children must fit into one of the four categories below:

  • Research not involving greater than minimal risk.
  • Research involving greater than minimal risk but presenting the prospect of direct benefit to the individual subjects.
  • Research involving greater than minimal risk and no prospect of direct benefit to individual subjects, but likely to yield generalizable knowledge about the subject’s disorder or condition.
  • Research not otherwise approvable which presents an opportunity to understand, prevent, or alleviate a serious problem affecting the health or welfare of children.

Parental permission for children to participate in research may be required by one or both parents, depending on the risk involved in the study. Generally, children over the age of 7 should also provide their assent to participate in the study.

For further information on how these populations are defined please refer to our Standard Operating Procedures and the federal regulations.