Risk Assessment of GM mosquito planned release is incomplete and lacks transparency, says GeneWatch UK

The Risk Assessment (RA) report of the Malaysian Genetic Modification Advisory Committee (GMAC) on the planned release of GM Aedes mosquitoes in Malaysia is incomplete and the RA process needs to be more transparent. These comments were made in a 13-page report by GeneWatch UK, a scientific organisation involved in genetic engineering and biosafety issues.

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’.

Malaysia’s field release of GM Aedes mosquitoes, purportedly developed by the IMR and the UK based biotech company Oxitec, will be one of the first such experiments in the world.

According to GeneWatch UK, the RA lacks the following elements:

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. Without looking at these papers, it is difficult to conclude or know the limitations of the models regarding the potential adverse effects and whether the likelihood of these can be determined.

There are also no models of disease transmission 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.

3. Views of Experts should be sought

According to GeneWatch UK ‘It is unclear whether GMAC ensured the inclusion of critical experts, as well as advocates, of this technology e.g. by contacting experts in India who have decided not to move to open release trials of Oxitec’s mosquitoes and/or by involving experts in disease transmission and other aspects that have not been addressed by the company’.

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 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.

GeneWatch UK says that such information is of secondary importance compared to understanding the basis (baseline) of how the existing natural mosquitoes interact with other species, viruses and humans.

GeneWatch UK 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 commercial release which may have unforeseen public health consequences.

This medical experiment would require radically different policy and regulatory measures than those used in any previous deliberate release of a GM organism.

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.

6. Role of the GM mosquito release experiments in a public health decision

Unlike clinical trials of medicines which have an established approval process for 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.

The full and referenced version of GeneWatch UK comments on Malaysian GMAC Risk Assessment for experimental releases of GM mosquitoes is available for download here: