Garfield High School
8 May 2012
Diarrhea can be deadly. While this statement may seem surprising, it is reality for many children and people around the world. Here in the U.S., diarrhea is an inconvenience for at most few days, but recovery is relatively rapid with clean water and electrolytes. However, what if there is no way to replace all the water and nutrients lost? What if the water isn’t sanitary? This is the case for many children around the world.
Neela comes from a village in rural Bangladesh. When she was 4 years old, she came down with terrible diarrhea for many days. She could not keep in food or water, and became malnourished and dehydrated. Due to poor water sanitation, most people in her village have come down with diarrhea at one time or another. The children in the village are especially hard hit – they have more severe diarrhea than the adults and take longer to recover. Fortunately, Neela’s mother was able to get help in the form of hydration salts and clean water from the WHO and UNICEF, so she was able to recover. This intervention comes too late for many of the children in the area.
An estimated 1.8 million people die each year from diarrheal disease, and approximately 90% of these deaths are children, most under age 5. The diarrhea is caused by a number of different pathogens including the Norwalk virus, Vibrio cholerae (the bacteria that causes Cholera), and E. coli. These pathogens spread easily in unsanitary conditions,
but their spread can be prevented or reduced with proper sanitation, or a vaccine. Both treatments are relatively expensive solutions for the developing countries that are ravaged by the disease.
Vaccines reduce diarrhea by provoking an immune response to the pathogen. Traditional vaccines (delivered intravenously) are difficult to store and transport because they need to be kept cold, which requires a reliable electricity grid, as well as refrigerated trucks. This requirement significantly increases the cost of these vaccines. In addition, traditional vaccines need trained medical personnel to deliver them. To significantly cut down costs in both refrigeration and personnel, scientists have been trying to develop vaccines that that keep well, can be transported easily, and can be administered by someone with basic health knowledge. These new types of vaccines, termed “edible vaccines” have
been engineered into plants. Easy to transport, these plants could be consumed either directly or in dehydrated form. These new vaccines are currently in development in genetically modified (GM) crops such as tomatoes, potatoes, bananas, and rice.
These plants are modified so they either make antibodies, or stimulate an immune response by carrying a non disease-causing part of the pathogen. GM plants have foreign DNA that has been inserted into the plant’s own genome. The
foreign DNA has been engineered with a marker gene that gives resistance to various antibiotics or herbicides.
Plant-derived vaccines, which are taken orally, differ from intravenous traditional vaccines in the type and level of immune response, or in quantity needed for proper immune response. Some of the oral vaccines, whether in pill form or whole plant form, provide a little better protection than the injected vaccine, since they enter the same way the pathogens do. However, since plant-based vaccines are not as “pure” and plant antibodies aren’t as effective as animal antibodies, a relatively higher dose of the antibody is needed. Since the crops used can’t be grown to an absolute
uniform size, each tomato, banana, or potato may contain a different vaccine dosage, which makes delivering the proper amount of medicine difficult. Scientists are working to alleviate this problem by processing the food. For example, one researcher dehydrated tomatoes and put them into a pill form. Some speculate that the vaccine could be delivered in processed food such as tomato juice, or some sort or processed chips from potatoes or rice.
In addition to some of the problems of varying dosage levels, and the relative amount of the food that might have to be eaten, there is the problem with GM crops in general. GM crops produce pollen that carries the genetic modification. If this pollen were released in the environment, it could spread resistance through the native plant population. Remember, the way these GM plants were selected was by inserting an herbicide-resistant or antibiotic-resistant gene into the plant’s genome. If released into the environment, native species could become resistant to herbicides and
antibiotics. One solution to this problem could be to grow GM edible vaccine crops, such as tomatoes, in a greenhouse.
Agatsuma Case Study: Edible Vaccines
Another objection to these crops comes from the feeling that these are not “natural” and that the agribusiness
companies that create them are not trustworthy. Since the diseases that these vaccines would target are in developing countries, there is not much of a monetary incentive for pharmaceutical companies to develop drugs. While philanthropists give some money, more money and research is needed in order to help reduce deaths in developing countries from such easily preventable and treatable diseases such as diarrhea.
To Think About
1. What is your gut reaction to the plants that have been genetically modified to produce vaccines?
2. Scientists are talking about creating many types of edible vaccines, including vaccines for disease such as
hepatitis B and measles, and the possibilities of vaccines for many other diseases exist. Would you feel
comfortable consuming these “edible vaccines” directly or indirectly (e.g. as a potato chip or a tomato pill)?
Why or why not?
3. These edible vaccines have had a few trials with animals, but are still very much in the experimental phase.
Scientists are still working out ways to get plants that produce the correct dosage and the right kinds of
antibodies. Do you think the promise of this new method of delivering vaccines is worth it? Do the benefits
outweigh some of the ethical concerns? Should the U.S. help developing countries train more health-care
workers and help them create infrastructure so that they could deliver vaccines?
4. Is the technology to make genetically modified plants that produce vaccine really the most logical and ethical
solution to the problem of diarrhea in the Third World? If poor water sanitation and unclean drinking water is
the source of most of these bacterial diseases, should more of the money be going into creating needed
infrastructure of a country instead?
5. Who should be responsible for the development and marketing of these types of products? Currently, most of
the research is being done in a few universities and some agricultural biotechnology companies. As a relatively
rich country, do we have an ethical responsibility for helping to pay for this research?
Agatsuma Case Study: Edible Vaccines
Ethics Analysis of the Case
Principles: The edible vaccines could do good by reducing the death rate from preventable diseases such as diarrhea.
They will hopefully reduce harm by keeping children alive, and providing a much less expensive (from the Third-World country’s perspective, not necessarily from all the primary research work being done in universities and ag-biotech
companies in the U.S.) way of delivering medicine that could save a child’s life. However, an escape of the GM pollen
into the environment might harm the ecosystem. Justice may be provided by developing needed technology in the U.S.
using U.S. resources, and then distributing the products to poorer countries; since we have the money and resources, we should do something about it. We might be reducing the autonomy of some of the people in the developing
countries because we are providing only one way of delivering the vaccine.
Virtues: What would a person who was virtuous do? If there is suffering in the world that can be solved by our
technology, should we do it? If we can help reduce the deaths of children, should we do it? How else might we go about helping children? Could we put in more sanitation systems or water treatment?
Outcomes Based: Our ultimate goal is to save the lives of children. This edible vaccine provides a less expensive way of delivering medicine, in terms of the need for trained doctors and nurses, equipment, and infrastructure. However, we don’t know the long-term consequences of consuming genetically modified foods. Could it contribute to other as of yet unknown diseases since the GM plants are taken into the body? What if the genes from these plants are spread into the environment? At one time, DDT was thought to be perfectly safe, but affected the ecosystem and caused long-term effects. How far into the future do we want to think? Do we look at immediate outcomes, or later ones?
Lesson Plan / Unit Connections
This case-study was developed as an introduction to a unit on GM foods. It could be used in connection to the immune system, or in a biotechnology unit.
Please also use the Annotated Bibliography to find more connections on GM foods and this particular topic. There are many resources available both on the internet and in print journals that have good information that can be used.
Agatsuma Case Study: Edible Vaccines
Ariza, LM. (2005, May) News Scan: Vaccines, Defensive Eating. Scientific American: 25.
This is a brief article about scientists at Arizona State University trying to develop edible vaccines (or more properly termed “food-derived vaccines”) to process into a useful pill. The article brings up the difficulties in getting the right dosage in different-sized fruits (tomatoes, bananas) or stems (potatoes). The tissues can be dried and then processed into a pill which can have advantages over traditional vaccines, such as easier transportation and storage.
Decision News Media. (2003, August 27) Edible vaccines closer to market [Web Page] In-Phramatechnololgist.com
Breaking News on Pharmaceutical Technology. Accessed 21 July 2008 from http://www.in-
This is a website about new product and market innovations. It appears to be pro-biotech, and it focuses on the commercial or industrial production of the vaccines or plant-derived medicine. Like many of the articles, it is brief on details, but mentions how money could be shifted from pharmaceutical companies to those that make GM foods.
Goforth, S and Tenenbaum, D. (2002) Devitt, T (Ed). The Why Files: Edible Vaccines [Web page]. Accessed 21 July 2008
This is a website from the University of Wiscosin Board of Regents that focuses on the science behind the news. It is aimed at the general public. It is maintained with help from the National Science Foundation and the National Institutes of Science Education. It has basic background on edible vaccines, the immune response, and a little about vaccine development.
Langridge, WHR. (2000, September) Edible Vaccines. Scientific American: 66 – 71.
This is a fantastic early review article showing all of the possibilities for edible vaccines. It is a good review of the early
research and promises of edible vaccines compared to traditional vaccines. It focuses on early mouse studies, and the crops that might be used (tomatoes, potatoes, bananas). It and has nice diagrams that show how to make a transgenic plant and that summarize the immune response.
Laim P, VG Ramachandran, R Goyal, and R Sharma (2007). Edible vaccines: Current status and future. Indian Journal of
Medical Microbiology. 25 (2): 93-102
This article is a brief review about the recent developments in edible vaccines It focuses on the recent research: how to make a plant-derived vaccine (e.g. how GM plants are made), recent animal trials, mostly in mice, and goes more into detail about the immune response to edible vaccines as compared to traditional vaccines. It goes into more depth about the advantages and disadvantages of the edible vaccines.
Michael D. MD Lemonick (2002). Medical and More: Tomato Vaccine [electronic version]. Inventor Charles Artnzen.
Time. Accessed 21 July 2008 from http://www.time.com/time/2002/inventions/med_tomato.html.
This is a brief commentary from Time Magazine, included in an article that focused on the best inventions in 2002. It is about how the tomato could be used for food-based vaccine development. The scientist who developed it wanted to focus on diarrhea because it is a preventable disease that kills so many children in the Third World.
National Science Foundation. (2000) Nifty50: Edible Vaccines [Web Page]. Accessed 21 July 2008 from http://www.nsf.gov/od/lpa/nsf50/nsfoutreach/htm/n50_z2/pages_z3/16_pg.htm#answer2
This is a website that celebrates the anniversary of the National Science Foundation by presenting 50 new inventions or research developments that are of scientific importance. It is a brief webpage with basic information about the promise of vaccines that could be developed using foods.
Pascual, DW. (2007, June 25) Vaccines are for dinner. Proceedings of the National Academy of Sciences. 104(25):
This is a very detailed review about recent developments in edible vaccines – it is probably more “scientific” that most
students could read, but it does provide a good overview of recent research and the crops that were used to make vaccines and how.
Agatsuma Case Study: Edible Vaccines
Schwartz, J. (2007 July 23) Research Shows Potential of Edible Vaccines. Ethics of Vaccines, University of Pennsylvania
Center for Bioethics [news and commentary web site]. Accessed 21 July 2008 from
This website condenses news to report on the possibilities of edible vaccines. It summarizes the results found in the Proceedings of the National Academy of Sciences. This is more of a “jumping off” point for issues. It is a good source because it deals with ethics and vaccine trials.
Yam, Philips. (2007, July) Updates: Edible Vaccines. Scientific American: 16.
This update, which is only a few paragraphs, talks about the newer foods being used to help develop vaccines for Hepatatis B. Researchers have used potatoes, but are trying to use bananas because they taste good to most children. No negative issues are brought up here, it is more suppositional so it may not be the most helpful.