Japanese Researchers Make Rice-Based Cholera Vaccine That You Can Eat

Cholera, an often deadly disease that comes from drinking contaminated water, is the target of a unique vaccine made in the form of edible genetically modified rice. According to the University of Tokyo, the edible vaccine has successfully completed its phase one human trial, proving effective at mounting an immune response against cholera.

The majority of vaccines come in the form of an injection, though some have been developed as nasal sprays and other non-invasion mediums. Perhaps the most unique is the edible rice vaccine, however, which is comprised of rice that was genetically modified under the university's MucoRice project.

Multiple cholera vaccines exist that don't require injections; they're administered as drops on the patient's tongue, but with a major downside: they are made from cholera cells and require cold storage, one of the biggest confounding factors when it comes to vaccines. The rice-based vaccine is different — it is designed to produce a non-toxic part of cholera toxin B.

When someone consumes the rice, their body's immune system reacts to the non-toxic CTB, which enters the body via intestinal membranes. This activity stimulates the immune system to produce two different antibodies against the invader, which is beneficial over injectable vaccines as they usually only trigger the production of one type of antibodies.

The vaccine, unlike most alternatives, doesn't require cold storage and can be kept stable at room temperature "from start to finish," according to the researchers. The rice is simply dried and powdered, then packaged in small doses. When someone is ready to take the vaccine, the rice is mixed with some water and consumed.

The phase 1 human trial proved promising, with the researchers noting that most of the participants experience a "good immune response" to the vaccine without experiencing any obvious side effects. Out of the 30 volunteers, the researchers found that 11 experienced little to no immune response.

Further analysis found that this may have been due to their gut microbiomes. Participants who responded well to the vaccine were found to have more diversified gut bacteria, while those who didn't respond well had poorer gut bacteria diversity. The findings underscore the importance of gut bacteria in human health, which is supported by things like eating probiotic foods and fiber.