Informed Consent

It is commonly understood that research, especially in the health sector, is designed to benefit future patients and society and not the individual study participant specifically. It is an accepted central principle that vulnerable people are entitled to a degree of protection that reflects their vulnerability. Thus, research participants should have three types of protection namely:

  • Protection from harm
  • Protection from exploitation
  • Protection from coercion and deception.

It is with this understanding, that Informed consent has four main features:

  • Consent involves an explicit act of agreement (verbal or written)
  • Participants are informed about and have an understanding of the research.
  • Consent must be given voluntarily without coercion
  • Consent must be renegotiable so that participants (especially those below the age of majority) may withdraw at any stage of the research process.

Some definitions:

In any research involving human participants – including information about or linked to human participants such as medical records or other health-related data – written informed consent is generally required.

Consent/informed consent

Informed consent refers to the process of fully informing adolescents and their parents/carers of the purpose of the research and what their involvement will be, prior to their decision to participate or not. It is an explicit agreement which requires participants to be informed about and have an understanding of the research. Informed consent must be given voluntarily and be renegotiable, so that children may withdraw at any stage of the research process (sometimes referred to as on-going or process consent / assent.


An informal agreement to participate in research. Assent is not universally recognised or agreed upon, with some advocating the use of consent in preference to assent.


Refusal to participate in research. Dissent may occur at any point during the research process. It may manifest as not signing a consent form, it may be verbally stated, or indicated by indirect verbal and non-verbal behaviours, such as saying “I’m tired”, or looking away from, or moving away from the researcher. Participants’ dissent should be respected even if this overrides parental/carer consent.

Proxy consent

A proxy consent for research participation constitutes a substituted judgement by a close relative or friend, based on knowledge of adolescent’s values, preferences, and view of life.

The proxy (person giving the consent on behalf of the research participant) must be informed and understand the fundamental aspects of research practice that:

Participation is voluntary and the consent can be withdrawn at any time the research is designed to benefit future patients and society as a whole, and not only the individual study participant; participation involves an incremental non-therapeutic risk (Berg et al; 2013: 408).

Waiver of consent

A waiver of consent (a signed informed consent form is not necessary) is given by the research ethics committee under certain circumstances, and it is normally provisional to:

  • The research involves no more than minimal risk to the participants;
  • The waiver or alteration will not adversely affect the rights and welfare of the participant(s);
  • The research could not practicably be carried out without the waiver or alteration;
  • Data from the participants is only collected after the research is complete.

Age of Adolescent:

The great majority of adolescents are under 18 years of age and therefore are considered not yet to have reached the age of majority and included in the age-definition of a child adopted by the Convention on the Rights of the Child1.

Other terms which overlap this definition include youth (defined by the United Nations as 15-24) and young people (10 -24 as defined by WHO).In some African countries, youth are defined as 15-34.2

The process to obtain ‘informed consent’ from adolescents is dependent on the age of the adolescent, and the legal rules and regulations of the country in which the research is taking place. Regulations may vary from country to country.

Considerable uncertainty exists about what constitutes appropriate levels of protection for adolescents as research participants and about the need for parental permission.

Vulnerable Populations:

A vulnerable population in terms of research populations could be defined as any group that is unable to protect its members’ self-interests in the course of being research participants and therefore, has an increased probability of being intentionally or unintentionally harmed. 

This definition includes population characteristics that limit the ability to obtain proper informed consent; these include language or cultural barriers and the lack of the necessary exposure to or understanding of the scientific method to comprehend risk or trial design.

Other vulnerable groups include those who need a guardian or proxy consent secondary due to minor age or lack of capacity, and populations that are so economically and socially disadvantaged that participation in medical research is viewed as the only option to access otherwise unavailable medical treatment. However, excluding subjects from research for the only reason of belonging to a vulnerable group is unethical and will bias the results of the investigation.

Critically ill research participants are the most vulnerable, yet essential population to have in some clinical studies and to reduce their vulnerability it is important that researchers spend enough time with the family members that provide proxy consent as discussed in the “Proxy consent” section above. Research guidelines and ethics procedures put safeguards in place to minimize the exploitation of ill patients and reduce the presence of any therapeutic misconception that may mislead the subject to participation in research (Silverman,2011).

Solomon (2011) identifies two other vulnerable populations, that are; the cognitively vulnerable and the economically vulnerable. He suggests that the cognitively vulnerable require extra protections while the economically vulnerable (that is the poor) should be protected by implementing existing regulations more appropriately and rigorously. He calls for the implementation of the distributive justice of the Belmont Report to safeguard against the exploitation of the economically vulnerable population groups. Researchers should further obtain guidance from community advisory boards on how to respect and uphold the dignity of the cognitively and economically vulnerable population groups (see the Community Engagements” section above).

Key questions for you to ask:

Who else do you need to consult to involve adolescents (above and below the age of majority) in the study?

  • Which adults, if any, do you need to meet in the family or local community to understand the needs and rights of the adolescents involved?
  • Whose consent do you need for adolescents below the age of majority?
  • What information will you need to provide them with?

What information do adolescents (above and below the age of majority) need to consent to being in the study?

  • What information do adolescents need to enable them to consider giving consent?
  • How will you find out the information adolescents need?
  • What procedures have been put in place to prevent adolescents from being coerced to participate?
  • What further information will adolescents need (in long-term or longitudinal projects) as the study progresses to enable them to consider their continued consent, and at what stages?

What form should the information provided to adolescents take?

  • Will you provide written information for support adolescents below the age of majority? If so, why?
  • If you do not provide written information, how will you convey the information? Why have you chosen this method?
  • Is there a designated person that participants and parents/guardians/caregivers or persons in authority can go it if she/he has any questions or concerns (now and in the future)?

Do adolescents below the age of majority require extra support to contribute?

  • How will you identify the special needs of individual participants?
  • How will you respond to these needs?

How will you asses the competence of adolescents to consent?

  • How will you ensure adolescents understand what consent is? How will you support adolescents below the age of majority to understand and weigh any risks?
  • How will you ensure that support adolescents below the age of majority are able to withdraw without negative consequences?
  • How will you ensure support adolescents below the age of majority understand that they are able to withdraw consent at any time without penalty?
  • How will you make provision for gaining informed consent from adolescents below the age of majority or allowing their dissent at different stages over long term projects

Other things to consider:

South Africa – Case study

In South Africa children under the age of 18 are legal minor and therefore not fully capable of acting independently without the assistance of an adult. However, South African legislators recognised that children have evolving capacity, and consequently passed laws that permit children to make certain decisions independently. However, it is difficult to establish any pattern between a child’s emerging capacity and the norms for various South African health interventions (Table 2 and Table 3). In South Africa the age of independent consent is as follows for these health interventions:

Table 3: South Africa – Health procedures/interventions for which children can consent independently: current and future 5

Procedure/InterventionAge at which child can consent independently in the futurePersons who can consent when children do not have capacity
Medical treatment12 + ‘sufficient maturity’Parent/legal guardian and a range of other persons can consent
Operations12 + ’sufficient maturity’ + parental/guardian assistanceParent/legal guardian caregiver and a range of other persons must assist
HIV Testing12Parent/legal guardian and a range of other persons can consent
Access to contraceptives12Parent/legal guardian and a range of other persons can consent
Terminations of pregnancyAny age 
Male circumcision16Parent/legal guardian and a range of other persons can consent
Research18Parent/legal guardian must consent.

Furthermore, South African public policy restraints on health research are as follows: “Therapeutic research must be in the best interests of the adolescent. Non-therapeutic research must be approved by the Minister of Health3

  • Therapeutic research – This is any research activity where the adolescent will directly benefit from the treatment or intervention.
  • Non-therapeutic research – This is a research activity where the adolescent does not directly benefit, but where there may be benefit in the future for others.

France & South Africa – Case study: Risk and inclusion of prevention as a medical treatment

Globally, there are 5 million young people aged 15–24 years living with HIV, and many more millions are at risk for HIV acquisition. However only France includes prophylaxis in its broad definition of medical treatment as “the treatment of a person for a current or a future condition that they may be at risk of contracting” which allows France to provide more holistic healthcare independently to qualifying adolescence5 Already many health practitioners provide preventative interventions within the scope of medical treatment such as contraceptive counselling, advice about the HPV vaccine and assistance with healthy diets and pre-exposure prophylaxis could be included as South African adolescents need an array of HIV prevention tools to address their risk of acquiring the life-long, stigmatized condition, that is HIV.


UPDATED NOV 22, 2023





Strode, A., Slack, C.M., Essack, Z., Toohey, J.D. and Bekker, L.G., 2020. Be legally wise: When is parental consent required for adolescents’ access to pre-exposure prophylaxis (PrEP)?. Southern African Journal of HIV Medicine, 21(1), pp.1-5.

Jaspan, H.B., Bekker, L.G., Grant, C.J., Slack, C.A., Strode, A.E. and Berwick, J.R., 2005. Protecting South Africa’s children from HIV; giving them our best shot: news & views. South African journal of science101(5), pp.216-217.

Berg, R.M.G., Møller, K. and Rossel, P.J.H., 2013. An ethical analysis of proxy and waiver of consent in critical care research. Acta Anaesthesiologica Scandinavica, 57(4), pp.408-416.

González-Duarte A, Zambrano-González E, Medina-Franco H, Alberú-Gómez J, Durand-Carbajal M, Hinojosa CA, Aguilar-Salinas CA, Kaufer-Horwitz M. II. THE RESEARCH ETHICS INVOLVING VULNERABLE GROUPS. Rev Invest Clin. 2019;71(4):217-225. doi: 10.24875/RIC.19002812. PMID: 31448777.

Merlo DF, Knudsen LE, Matusiewicz K, Niebrój L, Vähäkangas KH. Ethics in studies on children and environmental health. J Med Ethics. 2007 Jul;33(7):408-13. doi: 10.1136/jme.2006.016212. PMID: 17601869; PMCID: PMC2598138.

Merlo DF, Knudsen LE, Matusiewicz K, Niebrój L, Vähäkangas KH. Ethics in studies on children and environmental health. J Med Ethics. 2007 Jul;33(7):408-13. doi: 10.1136/jme.2006.016212. PMID: 17601869; PMCID: PMC2598138.

Solomon, S.R. (2013). Protecting and Respecting the Vulnerable: Existing Regulations or Further Protections? Theor Med Bioeth. 2013 Feb; 34(1): 17–28. doi: 10.1007/s11017-013-9242-8

Silverman, H. (2011).  Protecting Vulnerable Research Subjects in Critical Care Trials: Enhancing the Informed Consent Process and Recommendations for Safeguards. Ann. Intensive Care 1, 8 (2011).