TWN Info Service
on Health Issues (Jan 11/01)
Malaysia’s Risk Assessment of GM Mosquito planned release is incomplete and lacks transparency says GeneWatch UK
In its 13 page report GeneWatch UK states that ‘We are concerned that the novelty of this application of GM technology has made regulators in several countries too dependent on advice provided by the company, which has a vested interest in speeding its products into the market place in order to generate financial returns for its investors’.
The following article highlights the report by
The full and referenced version of the report is available for download here:
With best wishes
According to GeneWatch
1. A full literature review
GMAC’s RA cited 27 scientific publications in its references. This is an incomplete review of the relevant literature in this field. ‘Without a comprehensive literature review, hazards may be missed or their importance underestimated’, says GeneWatch.
For example, the effects of the GM mosquito releases on the evolution of the dengue virus and on human immunity are regarded important in the scientific literature but they are not listed in the references. Therefore it is unclear whether these effects were considered by the GMAC in the RA.
2. Ecological models omitted and lack of disease transmission modelling
Ecological and disease transmission modelling plays an important role in RA. Without such modelling it is impossible to predict the complex interactions between predators and prey, GM and wild type mosquitoes, and effects such as co-evolution of the dengue virus.
Although Oxitec has developed ecological models to try to predict the consequences of releasing GM mosquitoes on the natural mosquito population, these papers were not cited in the RA bibliography.
This is surprising as their conclusions and limitations provide important information about potential adverse effects and whether the likelihood of these can be determined.
However, no models of disease transmission appear to have been published by Oxitec or cited in the RA. This is problematic because several authors have warned that a reduction in human immunity combined with residual disease transmission from A. aegypti or A. albopictus (mosquitoes that transmit dengue) could result in a ‘rebound’ effect.
A ‘rebound’ effect refers to a situation in which the amount of serious diseases increases, despite a reduction in the numbers of A. aegypti mosquitoes.
In addition, no models of the potential evolution of the dengue virus appear to have been published by Oxitec or cited in the RA.
Modelling is also critical to establish the ‘release ratios’ needed to maintain populations below the threshold for disease transmission because a reduction in disease transmission that is not sustained can be disastrous due to the expected reduction in immunity.
Also, this will impact on ongoing costs and cost-effectiveness of any sustained commercial releases in the future.
3. Seeking the views of Experts (Expert Elicitation)
‘The lack of a formal expert elicitation process,
informed by a prior literature review and more sophisticated ecological
and disease modelling has limited the value of the RA process’, says
This is a recognised method of obtaining inputs from experts to RA processes. It is used to help identify and address uncertainties.
According to GeneWatch
It added that ‘the lack of transparency about how GMAC reached its decisions on risk characterisation (particularly the ranking of hazards and their likelihood and consequences) is of significant concern’.
4. A step-by-step approach was lacking
This would require as a first step before any open GM mosquito release, the development of computer models that include both of the two dengue-transmitting mosquito species; their predators and prey; all four serotypes of the dengue virus; other diseases known to be transmitted by these species; and the impacts of these viruses on human health (including the role of infection by more than one virus and the relevant interactions with immunity and severity of disease).
The lack of a step-by-step approach raises doubts about the justification for the proposed open release experiments i.e. to compare and evaluate the longevity, dispersal distance, the form and structure (morphology) and life history traits of the GM mosquito.
It adds that: ‘The very limited existing understanding of the relevant natural systems and of the stability and characteristics of the GM mosquito suggests that open release experiments are premature’.
5. GM mosquito release is a medical experiment
There is a lack of a full appreciation of the novelty of the GM mosquito release and the importance of scientific unknowns and uncertainties.
The use of GM mosquitoes to reduce dengue is entirely novel in that it is a medical experiment, potentially leading to a large scale public health intervention in the future (i.e. large scale commercial releases).
This makes the proposed releases radically different to any previous deliberate release of a GM organism in the policy and regulatory issues that they raise as well as in the novelty of the technology.
Although GMAC’s considerations of the proposed mosquito releases comes under the Biosafety Act which had been developed to implement the Cartagena Protocol, to which Malaysia is a party, this is not sufficient.
While risks to human health posed by GMOs are taken into account in RAs under the Cartagena Protocol, assessing the pros and cons of public health interventions is not central to its purpose. Hence experimental release of GM mosquitoes which should be regarded as a medical experiment need to be governed by other laws and international guidelines.
Persons potentially affected by such medical experiments must be adequately informed of the aims and anticipated benefits and potential risks of the GM mosquito release.
6. Role of the GM mosquito release experiments in a public health decision
There is a lack of a process to identify information needed to make a policy decision whether or not to release the GM mosquitoes on a commercial scale.
Ultimately, experimental releases of GM mosquitoes are intended to inform a decision about a potential public health intervention in the future. However unlike clinical trials of medicines which play a clear role in the approval process by testing both the efficacy and safety of the drug concerned, there is no clearly established process for approval of a commercial scale release of GM mosquitoes.
GeneWatch UK recommends that the GMAC clarifies its views on the role of the experiments in its decision-making process and what questions it regards as needing to be answered, e.g. regarding long term risks, efficacy and cost effectiveness in order to provide necessary public information regarding the aims, purposes and justification for these medical experiments.
To reach a fully informed decision on future releases, the Malaysian government will need to weigh up the pros and cons of releasing GM mosquitoes which includes social, ethical and economic costs, alternatives and other health priorities as well as public and expert opinions on these matters.