Continued from part 1
In global health, one of the most promising near-term uses of gene editing involves research on malaria. Although insecticide-treated bed nets and more effective drugs have cut malaria deaths dramatically in recent decades, the parasitic disease still takes a terrible toll. Every year, about 200 million cases of malaria are recorded, and some 450,000 people die from it, about 70 percent of them children under five. Children who survive often suffer lasting mental and physical impairments. In adults, the high fever, chills, and anemia caused by malaria can keep people from working and trap families in a cycle of illness and poverty. Beyond the human suffering, the economic costs are staggering. In sub-Saharan Africa, which is home to 90 percent of all malaria cases, the direct and indirect costs associated with the disease add up to an estimated 1.3 percent of GDP—a significant drag on countries working to lift themselves out of poverty.
With sufficient funding and smart interventions using existing approaches, malaria is largely preventable and treatable—but not completely. Current tools for prevention, such as spraying for insects and their larvae, have only a temporary effect. The standard treatment for malaria today—medicine derived from artemisinin, a compound isolated from an herb used in traditional Chinese medicine—may relieve symptoms, but it may also leave behind in the human body a form of the malaria parasite that can still be spread by mosquitoes. To make matters worse, the malaria parasite has begun to develop resistance to drugs, and mosquitoes are developing resistance to insecticides.
Efforts against malaria must continue to make use of existing tools, but moving toward eradication will require scientific and technological advances in multiple areas. For instance, sophisticated geospatial surveillance systems, combined with computational modeling and simulation, will make it possible to tailor antimalarial efforts to unique local conditions. Gene editing can play a big role, too. There are more than 3,500 known mosquito species worldwide, but just a handful of them are any good at transmitting malaria parasites between people. Only female mosquitoes can spread malaria, and so researchers have used CRISPR to successfully create gene drives—making inheritable edits to their genes—that cause females to become sterile or skew them toward producing mostly male offspring. Scientists are also exploring other ways to use CRISPR to inhibit mosquitoes’ ability to transmit malaria—for example, by introducing genes that could eliminate the parasites as they pass through a mosquito’s gut on their way to its salivary glands, the main path through which infections are transmitted to humans. In comparable ways, the tool also holds promise for fighting other diseases carried by mosquitoes, such as dengue fever and the Zika virus.
It will be several years, however, before any genetically edited mosquitoes are released into the wild for field trials. Although many questions about safety and efficacy will have to be answered first, there is reason to be optimistic that creating gene drives in malaria-spreading mosquitoes will not do much, if any, harm to the environment. That’s because the edits would target only the few species that tend to transmit the disease. And although natural selection will eventually produce mosquitoes that are resistant to any gene drives released into the wild, part of the value of CRISPR is that it expedites the development of new approaches—meaning that scientists can stay one step ahead.
THE PATH FORWARD
Like other new and potentially powerful technologies, gene editing raises legitimate questions and understandable concerns about possible risks and misuse. How, then, should the technology be regulated? Rules developed decades ago for other forms of genetic engineering do not necessarily fit. Noting that gene-edited organisms are not transgenic, the U.S. Department of Agriculture has reasonably concluded that genetically edited plants are like plants with naturally occurring mutations and thus are not subject to special regulations and raise no special safety concerns.
The benefits of emerging technologies should not be reserved only for people in developed countries.
Gene editing in animals or even humans raises more complicated questions of safety and ethics. In 2014, the World Health Organization issued guidelines for testing genetically modified mosquitoes, including standards for efficacy, biosafety, bioethics, and public participation. In 2016, the National Academy of Sciences built on the WHO’s guidelines with recommendations for responsible conduct in gene-drive research on animals. (The Gates Foundation co-funded this work with the National Institutes of Health, the Foundation for the National Institutes of Health, and the Defense Advanced Research Projects Agency.) These recommendations emphasized the need for thorough research in the lab, including interim evaluations at set points, before scientists move to field trials. They also urged scientists to assess any ecological risks and to actively involve the public, especially in the communities and countries directly affected by the research. Wherever gene-editing research takes place, it should involve all the key stakeholders—scientists, civil society, government leaders, and local communities—from wherever it is likely to be deployed.
Part of the challenge in regulating gene editing is that the rules and practices in different countries may differ widely. A more harmonized policy environment would prove more efficient, and it would probably also raise overall standards. International organizations, especially of scientists, could help establish global norms. Meanwhile, funders of gene-editing research must ensure that it is conducted in compliance with standards such as those advanced by the WHO and the National Academy of Sciences, no matter where the research takes place.
Finally, it’s important to recognize the costs and risks of failing to explore the use of new tools such as CRISPR for global health and development. The benefits of emerging technologies should not be reserved only for people in developed countries. Nor should decisions about whether to take advantage of them. Used responsibly, gene editing holds the potential to save millions of lives and empower millions of people to lift themselves out of poverty. It would be a tragedy to pass up the opportunity.