Edible Vaccines – A Future with Delicious Vaccines
“Let’s move forward to few years from now, it is one of those relaxing Sunday mornings, and you have a fruit bowl for breakfast. You pick up a cube of mango on a fork and place it in your mouth to feel the taste of its delicious pulp.
And boom, your immune system is now updated against the recent virus!”
During the current pandemic of COVID-19, one thing that we all learned was the medical miracle of vaccines, how they build our immune system and protect us from several contagious diseases. But, at the same time, another fact that this pandemic taught us was mass vaccination is not an easy task. From storing vaccines at appropriate temperatures and utilizing them before their expiration to massive-scale production and distinguishing priority groups among huge populations, even the most prepared healthcare systems encounter numerous challenges during large-scale vaccination. And, also it isn't easy for the consumers, as they have to wait in long lines before their turn, plus let's admit no one of us likes to get jabbed.
So, let’s imagine that in the foreseeable future, getting vaccinated would be as simple as eating a bowl of fruits for breakfast, and in fact, we would be growing our own vaccines in our yards. You might find this idea a little bizarre, but it is really possible. Scientists have been researching edible vaccines since the last century, and it is one of the most fascinating research topics of the 21st century.
In their article (Plant Based Vaccines and Therapeutics), microbiologist and infectious disease researchers Gary Kobinger and Hugues Fausther-Bovendo says,
“There are already vaccines out there like this that work — this is not as new an idea as it sounds — and plant-made vaccines offer several advantages over and above how most vaccines are made today.”
The Past
In the year 1983, scientists started incorporating transgenes in plants to produce transgenic plants with enhanced traits. (Grunewald et al., 2013)
This transgenic technology inspired Dr. Charles Arntzen to integrate antigen genes into the genome of surrogate plants and create specialized antigen-containing plants.
In 1990 a transgenic tobacco plant was successfully engineered as 1st edible vaccine against hepatitis B antigen. It was a milestone in edible vaccine production. (Saxena et al., 2014).
Edible vaccines are one of the most researched topics in the current era. Molecular farming aims to produce safe as well as inexpensive means of mediation and vaccination.
“The use of plants for the production of therapeutic proteins, called molecular farming, was proposed as an alternative biomanufacturing method in 1986, successes have revived interest in plant-produced pharmaceuticals for human use, which could include edible drugs.”
(Fausther and Kobinger, 2021)
How Are Vaccines Produced?
In her article about edible vaccines, Sophie Putka writes that most of the vaccines in the world are being produced by a self-contained organic method. Over 80% of vaccines for flu are manufactured inside chicken eggs. While remaining vaccines are produced within the cell cultures of insects and mammals.
According to Brazilian Journal of Medical and Biological Research these procedures are very expensive and unaffordable for many countries.
“The process of production and purification makes them expensive and unaffordable to many developing nations. An edible vaccine reduces the cost of production of the vaccine because of ease of culturing.”
Production of Edible Vaccines
In conventional process of edible vaccines production manufacturers incorporates a transgene (encoding an antigen protein against a particular disease) into the genome of selected plant tissues.
Numerous techniques are used to synthesize these vaccines; however, the commonly used processes are Agrobacterium-mediated transfer of genes and transformation through genetically altered plant viruses.
But, with the development of science and technology, scientists have also designed many modern techniques for efficient production of plant-based vaccines. Electroporation, sonication, biolistic, agroinfiltration, PEG treatment and virus-like particle (VLP) technology are few innovative techniques to create edible vaccines.
Why Edible Vaccines?
Now, a question arises that when traditional vaccines were already available as a successful immunizing agent, then what was the need for edible vaccines?
Internist Jaya Thomas and Vrinda M Kurup, explained five fundamental reasons why edible vaccines may supplant traditional vaccines:
· Edible vaccines are not only economical and bio-friendly but can also be easily administered with minimum storage issues. These qualities make them more valuable, especially in developing countries.
· Unlike traditional vaccines, edible vaccines can stimulate both systemic, as well as mucosal immunity.
· Edible vaccines require simpler manufacturing processes.
· Their production is highly efficient. According to statistics, only 40 acres of land can fulfill the hepatitis B vaccine requirement for the entire population of China; moreover, only 200 acres of land is enough for the vaccine production of all the infants in the world.
· The oral vaccine delivery by edible products, like plants, algae, yeast, lactic acid, etc., eliminates the need for medical professionals or sterile syringe conditions. (Kurup & Thomas, 2020)
Progress So Far
Currently, many edible vaccines are under development for various diseases, including measles, cholera, and hepatitis B, C, & E, while many more are in clinical trials.
Recently, a plant-based influenza vaccine has shown promise under phase 3 clinical trials. Researchers are also looking forward to developing plant-based vaccines for HIV, Ebola, and even COVID-19.
Edible Vaccines for COVID-19
Two plant-based vaccines candidates, coronavirus virus-like particle (CoVLP) and Kentucky Bioprocessing (KBP)-201, are currently under clinical trials, and several others are in the preclinical stage.
According to interim results of clinical trials, the CoVLP vaccine has proved to be highly efficient and safe; moreover, its neutralizing antibody responses are also relatively ten times stronger than the plasma of a convalescent patient.
Currently, the vaccine is being studied in a large-scale collaborative phase 3 clinical trial involving multiple countries with active VOC circulation.
Future Perspective and Conclusion
Every year, almost thirty million children around the globe miss out on even the most basic vaccines, which results in the death of at least three million from conditions that are easily preventable by vaccines. The idea of mass production of edible vaccines for various diseases may appear to be a simple solution to immunize such children. They are easily administered, lack any storage issues, and provide a readily acceptable delivery system for patients of various ages while remaining financially viable.
However, edible vaccines are still in the preclinical stages of development. The researchers highlight several barriers impeding the successful production of these third-generation vaccines that must be overcome before entering an era of edible vaccines. Despite constraints, scientists are still making continuous efforts to develop effective vaccines for numerous human and animal diseases. Since by well-popularizing and sharing them, they will be able to eradicate many diseases saving millions of lives.
Conclusion
· Grunewald, W., Bury, J., & Inzé, D. (2013). Thirty years of transgenic plants. Nature, 497(7447), 40-40.
· Kurup, V. M., & Thomas, J. (2020). Edible vaccines: promises and challenges. Molecular biotechnology, 62(2), 79-90.
· Saxena, J., & Rawat, S. (2014). Edible vaccines. In Advances in biotechnology (pp. 207-226). Springer, New Delhi.
· Fausther-Bovendo, H., & Kobinger, G. (2021). Plant-made vaccines and therapeutics. Science, 373(6556), 740-741.
· Hudu, S. A., Shinkafi, S. H., & Shua, U. (2016). An overview of recombinant vaccine technology, adjuvants and vaccine delivery methods. Int J Pharm Pharm Sci, 8, 19-24.
· Kurup, V. M., & Thomas, J. (2020). Edible vaccines: promises and challenges. Molecular biotechnology, 62(2), 79-90.
· Gunasekaran, B., & Gothandam, K. M. (2020). A review on edible vaccines and their prospects. Brazilian Journal of Medical and Biological Research, 53(2).
· Laere, E., Ling, A. P. K., Wong, Y. P., Koh, R. Y., Mohd Lila, M. A., & Hussein, S. (2016). Plant-based vaccines: production and challenges. Journal of Botany.
· Jan, N., Shafi, F., Hameed, O., Muzaffar, K., Dar, S., & Majid, I. (2016). An overview on edible vaccines and immunization. Austin Journal of Nutrition and Food sciences, 4, 1078.
· Laere, E., Ling, A. P. K., Wong, Y. P., Koh, R. Y., Mohd Lila, M. A., & Hussein, S. (2016). Plant-based vaccines: production and challenges. Journal of Botany.
Blogs
· https://www.inverse.com/mind-body/eat-your-vaccines
· https://www.news-medical.net/news/20210719/Plant-based-vaccines-for-COVID-19-and-other-viruses.aspx
· https://www.laboratoryequipment.com/578305-The-Progress-and-Promise-of-Plant-made-Vaccines/
By: Hadia Islam
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