# Myths and Realities about Genetically Modified Food: A Risk-Benefit Analysis
## 4 The Application of GMOs to Agriculture and Food Production
### Functional Food: Edible Vaccines  
Humans have used plants as therapeutic products for thousands of years because they are a reservoir of valuable pharmacological compounds [87]. Plants have recently become an appealing platform for edible vaccine production. As conventional vaccine development is lengthy and costly, disease outbreaks might become extremely difficult to manage in  
\begin{table}
\begin{tabular}{c c c c c} \hline
**GM Crop** & **Substance** & **Risk** & **Modification** & **Effect** \\ \hline Snowden Potato & Acrylamide & \begin{tabular}{c} Carcinogen \\ (Group 2A) \\ \end{tabular} & \begin{tabular}{c} Pyruvate \\ decarboxylase \\ overexpression \\ \end{tabular} & 69\% reduction [109] \\ \hline Innate Potato & Acrylamide & \begin{tabular}{c} Carcinogen \\ (Group 2A) \\ \end{tabular} & \begin{tabular}{c} RNAi gene \\ silencing \\ technology \\ \end{tabular} & 52–78\% reduction [110] \\ \hline Wheat & Gluten & \
\begin{tabular}{c} Coeliac \\ disease \\ \end{tabular} &
\begin{tabular}{c} Gliadin content \\ reduction \\ \end{tabular} & 97\% reduction [111] \\ \hline \end{tabular}
\end{table}
Table 4: Healthier crops obtained through GE.  
many situations. For example, in the first 6 months of the COVID-19 pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused more than 1 million deaths and wreaked havoc on both the global economy and social order. To prevent further morbidity and mortality, developing an effective vaccine and antiviral therapy against this virus is a pressing need [120]. Edible vaccines seem a superior alternative, especially in developing countries, as they need no pre-administration treatment or purification, are less costly to produce, are simpler to administer, pose no storage difficulties, and are bio-friendly [121]. The Spike (S) protein gene or a component of Spike, such as the S1 subunit, can be cloned into a plant expression vector. The generated transgenic plants may be eaten and readily and orally administered to immunize humans against the newly emerged virus [120].  
Additionally, recent studies have shown that edible vaccines stimulate both systemic and mucosal responses, and the area required for oral vaccine production for all infants worldwide covers only 200 hectares [122]. Most studies have used cultivated potatoes, which appear to be an appropriate model for producing vaccines against tetanus, diphtheria, or hepatitis B [121]. However, potatoes might not be the best choice of edible vaccines because cooking can weaken most antigenic proteins [123]. Rice is another plant species used to develop edible vaccines. It might have a severe public health impact because rice is a staple food and shows a high antigen expression. Banana is also used frequently for producing edible vaccines because it does not need cooking. Tomatoes, maize, tobacco, bananas, carrots, and peanuts are plant species with a much brighter future as edible vaccines (Figure 7). Nevertheless, many plant species, such as lettuce, papaya, quinoa, and tobacco, are being studied to create edible vaccines. Of the main diseases for which food vaccines are developed, rabies (spinach), hepatitis B (potato and lettuce), cholera (rice), diarrheal diseases (potato and maize), and anthrax (tomato and spinach) are noteworthy. In 2005, the WHO held a meeting about the regulatory assessment of plant-based vaccines, which concluded and established that existing guidelines for the development, evaluation, and use of vaccines, following conventional methods, can be applied to produce edible vaccines. Although the discovery of edible vaccines is one of the main breakthroughs on the biotechnology branch, the main challenge is for the public to approve them. As their benefits are prominent enough to overcome their side effects, appropriate research is necessary to make the better control of infectious diseases possible [121].