TWN Briefing Note on Risk Assessment for SBSTTA-26

TWN Info Service on Biodiversity/TK and Biosafety
10 May 2024
Third World Network

Dear Friends and Colleagues,

TWN Briefing Note on Risk Assessment for SBSTTA-26, May 2024

Parties to the Cartagena Protocol on Biosafety will gather in Nairobi for the Twenty-sixth meeting of the Subsidiary Body on Scientific, Technical and Technological Advice from 13-18 May 2024. A key item for discussion is the draft guidance materials for risk assessment of living modified organisms containing engineered gene drives (EGD-LMOs).

This TWN Briefing Note highlights some of the key elements of the draft guidance, while pointing to how risks and uncertainties of EGD-LMOs are insufficiently addressed. In this regard, recommendations include a call for further work on the draft guidance materials and appropriate modalities to improve the materials. In addition, the proper application of the procedure for avoiding or managing conflicts of interest in expert groups, and the conduct of a wider assessment of the socioeconomic, cultural, and ethical impacts of EGD-LMOs are needed. Ultimately, the precautionary approach needs to be applied and no release of high risk and unassessed EGD-LMOs should occur.

With best wishes,
Third World Network


Risk assessment and risk management (Agenda Item 6)
TWN Briefing Note for SBSTTA-26, May 2024


In decision 14/19 (paragraph 9), Parties to the Convention on Biological Diversity (CBD) recognised that specific guidance may be useful for living modified organisms containing engineered gene drives (EGD-LMOs) due to their potential adverse effects. The decision also sets out precautionary conditions that should be met before any consideration of introducing such organisms into the environment, including for experimental releases and research and development purposes, given the uncertainties.

Subsequently, the 2020 Ad Hoc Technical Expert Group (AHTEG) on Risk Assessment concluded that there was a need for further guidance material on EGD-LMOs, due to the fundamental challenges they pose to current risk assessment methodologies.

This conclusion was based on various biological and conceptual novelties of EGD-LMOs, including their explicit design intention of spread and persistence within wild populations, across a potential range of receiving environments. EGD-LMOs are also described as moving the ‘lab to the field’ due to the inclusion of genetic engineering processes at every generation following environmental release, increasing uncertainties and potential for next-generation effects.

Without the availability of full proof mitigation methods or the ability to recall EGD-LMOs, risk assessment guidance needs to be comprehensive in tackling such risks and uncertainties.

In 2022, Parties to the Cartagena Protocol on Biosafety therefore agreed to develop such guidance materials on risk assessment of EGD-LMOs and established a new AHTEG on Risk Assessment to carry out this task. They further specified that the materials should have a specific focus on engineered gene drive mosquitoes, given that these applications are currently the most developed.

Risk assessment guidance materials  

The draft guidance contained in CBD/SBSTTA/26/5/Add.1 is a first attempt and provides a starting point, including with regard to the identification of risks associated with mosquito applications and in the identification of various uncertainties associated with EGD-LMOs. These uncertainties include the lack of ability to isolate self-sustaining gene drives that are designed to have unlimited spread, including during any phased approach for trial releases. Risks of EGD-LMO mosquitoes and uncertainties are comprehensively covered in the guidance and provide valuable information on potential adverse effects that may result from EGD-LMO releases.

However, the draft guidance materials lack detailed methodological guidance that is able to comprehensively address the associated risks and uncertainties of EGD-LMOs (see Box). There is an overemphasis on describing a new methodology (problem formulation/pathways to harm approach), but not how it can be applied to address risks specifically related to EGD-LMOs. The general section of the document does not go beyond assessing risks of current (non gene-drive) LMOs.

Key risks of EGD-LMOs insufficiently addressed

  • Further guidance is needed to address the central risks and uncertainties of EGD-LMOs, e.g. gene flow to non-target organisms, unanticipated effects and interactions, and unintended spread beyond target sites. The methodology proposed and examples given are largely based on standard LMO assessment methods that do not necessarily address the specific risks of EGD-LMOs.
  • There is a lack of identification of, and guidance on, risks that apply to applications outside of mosquito vector control, such as EGDs in mammals and fish or other insects (e.g., conservation applications). Also, the risk of an EGD-LMO designed to target invasive species escaping back to their native range, where they are indigenous, is not fully considered.
  • There is inadequate identification of, and guidance regarding, potential unintended behaviours of EGD-LMOs. For example, unintended chasing dynamics of cyclical population crashes and repopulation with wild populations (rebounds) may result in lack of efficacy and may also increase uncertainties and risks, including the long-term risk of escape from target site areas.
  • There is an over-reliance on assumptions regarding the functioning of EGD-LMOs and ‘behaving according to design’ aims without due consideration of what may happen when their function or behaviour deviates from these assumptions.
  • There is a lack of guidance on how to identify protection goals/assessment end points.
  • The ‘pathways to harm’ approach requires advance knowledge of potential mechanisms (pathways) by which risks may manifest e.g. how the EGD-LMO may behave, and detailed knowledge of the receiving environment/s and likely interactions. This hypothesis-driven approach does not sufficiently incorporate knowledge gaps and uncertainties.
  • The inclusion of a tiered-testing method (more commonly applied to toxicology) favours a minimised empirical testing approach that is not sufficiently precautionary for EGD-LMOs.
  • There is an over-reliance on modelling to address risks and uncertainties. The limitations of modelling need to be further elucidated and clarified.
  • The phased approach recommended fails to acknowledge the inability to confine gene drives, rendering it an inadequate methodology for field trial releases of EGD-LMOs.
  • There is an over-reliance on monitoring for adverse effectsto address risk/uncertainties, but this is not compatible with a precautionary approach for a technology that lacks mitigation methods and is difficult to recall.
  • There is a lack of guidance on how to address uncertainties. It would be more helpful to provide guidance on ‘cut-off criteria’, i.e. when a risk assessment cannot provide the required certainty needed for going ahead with environmental release. In this regard, the document could be strengthened with guidance relating to: (i) when a risk assessment cannot be finalized; (ii) describing in detail the conceptual and practical challenges of implementing the methodological steps; and (iii) difficulties in operationalizing protection goals due to knowledge gaps in defining and identifying assessment endpoints.

Further gaps that need to be addressed

The guidance identified numerous aspects of EGD-LMOs that raise important socio-economic considerations. These include the potential to increase dependency on technological fixes; potential adverse impacts on biodiversity with economic, cultural, ecological and ethical implications; and potential impacts on the reciprocal relationship with biodiversity. The guidance thus recommends that attention be given to the “socio-economic, cultural, traditional, religious, or ethical concerns that may be considered in the decision-making process”.

The AHTEG also highlighted the importance of considering alternative strategies to the release of EGD-LMOs, taking into account issues such as long- term health impacts. These include “unintended evolution of pathogens, reduced capability to control target organisms with conventional methods, increased human and animal disease transmission, and compatibility with other vector control methods”. The guidance further clarifies that “[t]he outcome of the risk assessment should be evaluated in regard to a broad range of comparators for the decision-making process”.

The AHTEG also noted that public awareness, education and participation, access to information and data availability is essential to ensure effective participation of indigenous peoples and local communities, including in the initial stages of identifying protection goals in the risk assessment process, as well as for obtaining their free, prior and informed consent.

Sufficient isolation was recognised to be potentially impossible for certain EGD-LMOs that “may eventually spread beyond release sites and establish across national borders, raising issues of transboundary movements and international governance”. Guidance on how to address this risk is not currently sufficient. For example, the issue of where liability lies, should damage occur, needs to be further considered.

Concerns over potential conflicts of interest

In the course of the AHTEG proceedings, concerns were raised over a potential conflict of interest involving a member of the AHTEG, and an associated failure by this individual to disclose the relevant situation in accordance with decision 14/33, which lays out the procedure for avoiding or managing conflicts of interest in expert groups. As a result of the concerns raised, and taking into account developments in other multilateral fora, the Secretariat has now proposed measures to improve the procedure.


  • Take note of the outcomes of the AHTEG and the draft guidance materials contained in CBD/SBSTTA/26/5/Add.1.
  • Propose further work on the draft guidance materials on risk assessment of EGD-LMOs, given the insufficiencies identified above and the short time period in which the work was carried out.
  • Define appropriate modalities to improve the guidance materials in the next intersessional period, focussing on the elements identified above, with a view to completing the work by COPMOP-12.
  • Ensure that the procedure for avoiding or managing conflicts of interest in expert groups, as contained in decision 14/33, is properly applied to AHTEG members.
  • The amendments proposed in Section A of the draft recommendation contained in CBD/SBI/4/11, to improve the procedure, should also be implemented, including the addition of a declaration by individuals to “undertake to recuse [themselves] from relevant discussions or decision-making, as appropriate”. At the same time, it should be ensured that due diligence from the Secretariat is applied to any potential conflicts of interest.
  • Adopt the recommendation that the AHTEG also develop guidance materials for the risk assessment of living modified fish.
  • Adopt the recommendation of the AHTEG for further work on self-limiting insects, as also recommended by the multidisciplinary AHTEG on Synthetic Biology.
  • Ensure the conduct of a wider assessment of the socioeconomic, cultural, and ethical impacts of engineered gene drives, in particular on indigenous peoples and local communities, as recommended by the multidisciplinary AHTEG on Synthetic Biology, as a complement to the draft guidance materials on risk assessment of such organisms. This could be undertaken in conjunction with a renewed mandate of the AHTEG on Socio-economic Considerations under the Cartagena Protocol, and/or through other relevant processes under the Convention.
  • Reaffirm the application of the precautionary approach and ensure no release of high risk and unassessed EGD-LMOs.
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