Tennessee House Bill HB1894 isn’t evidence that vaccines are present in food at grocery stores; edible vaccines remain hypothetical for now

On 21 February 2024, the Tennessee House of Representatives passed a bill (HB1894) on food labeling sponsored by lawmaker Scott Cepicky. The bill “prohibits the manufacture, sale, or delivery, holding, or offering for sale of any food that contains a vaccine or vaccine material unless the food labeling contains a conspicuous notification of the presence of the vaccine or vaccine material in the food”.

The voting was preceded by a hearing in which Cepicky laid out his argument supporting the need for this legislation. Video clips of the hearing went immediately viral on Instagram, Twitter, and TikTok, where many interpreted the discussion as evidence that edible vaccines were already or about to be introduced into the market.

Some social media users suggested that these products were a way to get everyone vaccinated against COVID-19. Others seized the opportunity for promoting “detox” products and supplements to prevent the alleged adverse effects of these vaccines.

Some linked the bill with earlier claims about mRNA COVID-19 vaccines being sneaked into the food supply through vaccinated livestock and genetically modified plants. Health Feedback and other fact-checking organizations reviewed these claims in 2023 and found them to be false.

Likewise, Cepicky’s speech during the hearing contains inaccuracies and is misleading. Vegetables and fruits in grocery stores don’t contain vaccines, and there is no evidence that they will any time soon, as we will show in this review.

Cepicky’s speech during the hearing contains inaccuracies

The main argument on which Cepicky based his defense of the bill is that several companies and research institutions have “already perfected the ability to put human vaccines” into certain foods, including lettuce, tomatoes, and tobacco products.

Suggesting that these products might inadvertently enter grocery stores at any time, he called for a consumer protection bill that guaranteed clear labeling of food products containing vaccines.

These remarks met with pushback from the chairman, John Ray Clemmons, who questioned the necessity for this legislation. “Is that even legal to do in the State of Tennessee? To sell [food products] with the vaccine in?” Clemmons asked.

Cepicky replied that he wasn’t “arguing that point”, adding that the bill is “to make sure that if you’re going in to buy tomatoes, and there’s a polio vaccine in there, that you are aware of what you’re buying has a polio vaccine”. Cepicky went on to express concerns that some people might be allergic to the vaccine or experience an “overdose” if eating too much of the product.

Without further context, Cepicky’s allegations are misleading because they suggest that edible vaccines, which is what these products are called, are now ready to use. This isn’t true. This technology is in the early stages of research and still faces several technical and regulatory hurdles. No human vaccine in food is commercially available or has been approved by regulatory agencies in the U.S. or anywhere else. Therefore, Cepicky’s bill is merely a preemptive measure, contrary to what some social media posts implied.

Moreover, the discussion overlooks the important fact that any medical treatment requires informed consent. Vaccines are no exception, regardless of the delivery mechanism. So if or when the technology becomes available, it is unlikely that such products will ever enter supermarkets and grocery stores. Instead, they would likely be administered under the supervision of a health professional.

Edible vaccines are still in early development

Edible vaccines are plants such as fruits and vegetables that are genetically modified to produce selected genes from harmful microorganisms. The resulting transgenic plants produce the proteins of interest and, when eaten, can generate an immune response in the person just like a traditional vaccine would do.

Because they are easy to produce, administer, and store, edible vaccines offer many potential advantages over traditional vaccines. For example, this technology can be particularly useful in developing countries, where challenges related to refrigeration during vaccine storage and transportation greatly limit access to vaccination.

The world’s first edible vaccine study dates back to 1997. Researchers at Cornell University produced a vaccine against the hepatitis B virus in genetically engineered potatoes. The vaccine showed promise in mice and as a booster dose in people already vaccinated against hepatitis B^[1]. However, the results also revealed challenges, like the difficulty in ensuring every person receives the same dose.

Currently, edible vaccines against several human and animal diseases are under development in potatoes, tomatoes, bananas, lettuce, spinach, corn, rice, and carrots^[2].

But apart from the general requirements of safety and efficacy, edible vaccines still need to overcome additional challenges, including batch-to-batch consistency, dosage standardization, and dependence on environmental factors. Also, the use of transgenic technologies adds further concerns in terms of biosafety and acceptance by the general public^[2].

During the hearing, Cepicky cited three specific research lines that were supposedly ready to use. One was led by the University of California Riverside, another by the University of California Berkeley, and the last one by the tobacco company R.J. Reynolds. We will address each of them below.

Research at the University of California Riverside

In 2021, the University of California Riverside received funding to develop a project in collaboration with the University of California San Diego and Carnegie Mellon University. The project aimed to develop edible vaccines in plants such as lettuce and spinach.

To do that, the researchers planned to insert mRNA in chloroplasts, disk-shaped structures that convert sunlight into chemical energy within plant cells, and which can also replicate genetic material of interest inside the cell.

But contrary to what Cepicky claimed, this technology “won’t be available for human use anytime soon,” Juan Pablo Giraldo, the project leader, told USA Today in 2021. “This research will take a couple of years to show proof of concept of the technology,” Girlando explained. And even after that, he remarked that “it will need more studies and several more years for people to use leafy greens as mRNA vaccine factories”.

Research at the University of California Berkeley

We couldn’t find any information about a project developing edible vaccines in tomatoes at this institution. However, similar research was published in February 2024 by a group of researchers in Uzbekistan^[3]. The researchers developed transgenic tomatoes that produced part of the spike protein of SARS-CoV-2.

The vaccine, called TOMAVAC, generated an immune response in mice and in 14 healthy adults.

But the Discussion section of the published study pointed out that this was only a “small-scale proof-of-concept study”. That is, future studies are still required to produce sufficient standardized TOMAVAC for clinical trials. And after that, large-scale studies would be needed to evaluate the safety of this approach, as well as the durability of the immune response and the protection provided.

Research by R.J. Reynolds Tobacco

Cepicky claimed that the vaccine by R.J. Reynolds Tobacco (now part of the company British American Tobacco) was ready to be introduced “into tobacco products”. However, this is incorrect because this vaccine candidate, while also plant-based, isn’t an edible vaccine but an injectable one.

R.J. Reynolds owns Kentucky BioProcessing, a U.S. biotech unit that did develop a COVID-19 vaccine candidate produced in the leaves of the tobacco plant Nicotiana benthamiana. But the plant isn’t edible and simply acts as a production factory as Hug Haydon, president of the company, explained to NPR.

In December 2020, the company announced plans to start a Phase I clinical trial of its COVID-19 vaccine candidate following approval by the U.S. Food and Drug Administration (FDA). The first results in mice were published in the journal Vaccine in November 2021^[4]. No results on humans have been published so far.

A Canadian biotech firm, Medicago, used the same approach to produce the world’s first plant-based COVID-19 vaccine, also in N. benthamiana leaves. Health Canada authorized Medicago’s vaccine for use in adults on 24 February 2022 after the vaccine showed an efficacy of 71% in clinical trials. Medicago canceled the authorization on 31 March 2023 due to the company’s closure. This vaccine was also not edible but delivered by intramuscular injection, in two doses.

Conclusion

Contrary to Cepicky’s allegations and to online claims, the technology for producing edible vaccines isn’t ready to use. While research on edible vaccines shows promise, the technology needs further development. For example, researchers need to standardize the dosage and scale up production before being able to evaluate the safety and efficacy of the candidates in large-scale clinical trials.

Grocery vegetables currently don’t contain vaccines, and such food vaccine products haven’t been authorized by regulatory agencies in any country. Even if edible vaccines become a reality, they would be subject to drug regulations and therefore unlikely to be distributed in supermarkets and grocery stores.

REFERENCES

• 1 –  Thanavala et al. (2005) Immunogenicity in humans of an edible vaccine for hepatitis B. PNAS.
• 2 –  Stander et al. (2022) Plant-Derived Human Vaccines: Recent Developments. BioDrugs.
• 3 –  Buriev et al. (2024) Tomato-made edible COVID-19 vaccine TOMAVAC induces neutralizing IgGs in the blood sera of mice and humans. Frontiers in Nutrition.
• 4 –  Royal et al. (2021) Development of a SARS-CoV-2 Vaccine Candidate Using Plant-Based Manufacturing and a Tobacco Mosaic Virus-like Nano-Particle. Vaccines.