Eat Your Vaccines

These are the Edible Veggies that were in the NIH trials  and highly recommended to facilitate the Vaccines.

Tobacco

The first edible vaccine was produced in tobacco in 1990 in which 0.02 % recombinant protein of the total soluble leaf proteins was found.

Besides, antibodies against dental caries, expressed in tobacco, are already in preclinical human trials. Italian researchers have now developed an immunologically active, cost-efficient vaccine against human papilloma viruses (HPV). 

Potato

Genetically modified potatoes are also a viable option and seem to be the desired vector. Many of the first edible vaccines were synthesized in potato plants. The transgenic potatoes were developed and grown by Arntzen and Mason and their research group at the Boyce Thompson Institute for Plant Research, Cornell University.

Attempts have also been made to boil the potatoes as raw potatoes are not very appetizing but unfortunately the cooking process breaks down about 50 % of the proteins in the vaccine. While some proteins are more tolerant to heat, for most proteins it will be necessary to amplify the amount of protein in the engineered foods if they are to be cooked before consumption. ( Good to know HEAT is an enemy!)

Tomato

Tomatoes are an excellent candidate because they are easy to manipulate genetically and new crops can be grown quickly. Moreover, they are palatable and can be eaten raw. While tomatoes do not grow well in the regions in which the edible vaccines are most needed, the engineered tomatoes can be dried or made into a paste to facilitate their delivery.

Banana

A common fruit—the banana—is currently being considered as a potential vehicle for vaccines against serious as well as too common diseases. The advantage of bananas is that they can be eaten raw as compared to potatoes or rice that need to be cooked and can also be consumed in a pure form. Furthermore, children tend to like banana and the plants grow well in the tropical areas in which the vaccines are needed the most.

Maize

Maize has also been used as a vector for various edible vaccines.

Researches are in offing at Iowa State University with the aim to allow pigs and humans to get a flu vaccination simply by eating corn or corn products. It is quite likely that corn vaccine would work in humans when they eat corn or even corn flakes, corn chips, tortillas, or anything that contains corn.

Rice

Rice is another potential crop which has been used for developing vaccines. It offers several advantages over traditional vaccines; it does not require refrigeration. In fact, the rice proved just as potent after 18 months of storage at room temperature and the vaccine did not dissolve when exposed to stomach acids.

Spinach

Genetically modified spinach has also been considered for the development of edible vaccine. 

Among other food crops with potential to be developed as edible vaccine; sweet potato, peanuts, lettuce, watermelon, and carrots are on the top priority. 

Edible vaccines would enhance compliance, especially in children, and because of oral administration would eliminate the need for trained medical personnel.  Their production is highly efficient and can be easily scaled up. For example, hepatitis B antigen required to vaccinate whole of China annually, could be grown on a 40-acre plot and all babies in the world each year on just 200 acres of land.

The specific advantages:

1.  Edible means of administration.

2.  No need of medical personnel and syringes.

3.  Sterile injection conditions are no more required.

4.  Economical in mass production by breeding compared to an animal system.

5.  Easy for administration and transportation.

6.  Effective maintenance of vaccine activity by controlling the temperature in plant cultivation.

7.  Storage near the site of use.

8.  Heat stable, thus eliminating the need of refrigeration.

9.  Enhanced compliance (especially in children).

10.  Delivery of multiple antigens.

11.  Integration with other vaccine approaches.

12.  Administration of edible vaccines to mothers to immunize the fetus-in utero by trans-placental transfer of maternal antibodies or the infant through breast milk. Edible vaccines have a potential role in protecting infants against diseases like group-B Streptococcus, respiratory syncytial virus (RSV), etc., which is under investigation.

Limitations and Challenges:

1.  Consistency of dosage from fruit to fruit, plant to plant, lot to lot, and generation to generation is not similar.

2.  Stability of vaccine in fruit is not known.

3.  Evaluation of dosage requirement is tedious.

4.  Selection of best plant is difficult.

5.  Certain foods like potatoes are generally not eaten raw and cooking the food might weaken the medicine present in it.

6.  Not convenient for infants as they might spit it, eat a part or eat it all, and throw it up later. Concentrating the vaccine into a teaspoon of baby food may be more practical than administering it in a whole fruit.

7.  There is always possibility of sideeffects due to the interaction between the vaccine and the vehicle.

8.  People could ingest too much of the vaccine, which could be toxic, or too little, which could lead to disease outbreaks among populations believed to be immune.

Regulatory Issues

It is still unclear whether the edible vaccines would be regulated under food, drugs. or agricultural products and what vaccine component would be licensed—antigen itself, genetically engineered fruit or transgenic seeds. They would be subjected to a very close scrutiny by the regulatory bodies in order to ensure that they never enter the food supply. This would include greenhouse segregation of medicinal plants from food crops to prevent outcrossing and would necessitate separate storage and processing facilities. Although edible vaccines fall under “Genetically modified” plants, it is hoped that these vaccines will avoid serious controversy, because they are intended to save lives.

Future Perspective and Conclusion

Thirty million children throughout the world do not receive even the most basic immunizations each year. As a result, at least three million of these children die from diseases that are fully vaccine-preventable. The solution to vaccinate these children might seem simple with the idea of large scale production of edible vaccines for various diseases.