Scientists Are Growing an Edible Cholera Vaccine in Rice
The world's attention has been focused on the coronavirus crisis but Yemen, Bangladesh and many others countries in Asia and Africa are also in the grips of another pandemic: cholera. The current cholera pandemic first emerged in the 1970s and has devastated many communities in low-income countries. Each year, cholera is responsible for an estimated 1.3 million to 4 million cases and 21,000 to 143,000 deaths worldwide.
Immunologist Hiroshi Kiyono and his team at the University of Tokyo hope they can be part of the solution: They're making a cholera vaccine out of rice.
"It is much less expensive than a traditional vaccine, by a long shot."
Cholera is caused by eating food or drinking water that's contaminated by the feces of a person infected with the cholera bacteria, Vibrio cholerae. The bacteria produces the cholera toxin in the intestines, leading to vomiting, diarrhea and severe dehydration. Cholera can kill within hours of infection if it if's not treated quickly.
Current cholera vaccines are mainly oral. The most common oral are given in two doses and are made out of animal or insect cells that are infected with killed or weakened cholera bacteria. Dukoral also includes cells infected with CTB, a non-harmful part of the cholera toxin. Scientists grow cells containing the cholera bacteria and the CTB in bioreactors, large tanks in which conditions can be carefully controlled.
These cholera vaccines offer moderate protection but it wears off relatively quickly. Cold storage can also be an issue. The most common oral vaccines can be stored at room temperature but only for 14 days.
"Current vaccines confer around 60% efficacy over five years post-vaccination," says Lucy Breakwell, who leads the U.S. Centers for Disease Control and Prevention's cholera work within Global Immunization Division. Given the limited protection, refrigeration issue, and the fact that current oral vaccines require two disease, delivery of cholera vaccines in a campaign or emergency setting can be challenging. "There is a need to develop and test new vaccines to improve public health response to cholera outbreaks."
A New Kind of Vaccine
Kiyono and scientists at Tokyo University are creating a new, plant-based cholera vaccine dubbed MucoRice-CTB. The researchers genetically modify rice so that it contains CTB, a non-harmful part of the cholera toxin. The rice is crushed into a powder, mixed with saline solution and then drunk. The digestive tract is lined with mucosal membranes which contain the mucosal immune system. The mucosal immune system gets trained to recognize the cholera toxin as the rice passes through the intestines.
The cholera toxin has two main parts: the A subunit, which is harmful, and the B subunit, also known as CTB, which is nontoxic but allows the cholera bacteria to attach to gut cells. By inducing CTB-specific antibodies, "we might be able to block the binding of the vaccine toxin to gut cells, leading to the prevention of the toxin causing diarrhea," Kiyono says.
Kiyono studies the immune responses that occur at mucosal membranes across the body. He chose to focus on cholera because he wanted to replicate the way traditional vaccines work to get mucosal membranes in the digestive tract to produce an immune response. The difference is that his team is creating a food-based vaccine to induce this immune response. They are also solely focusing on getting the vaccine to induce antibodies for the cholera toxin. Since the cholera toxin is responsible for bacteria sticking to gut cells, the hope is that they can stop this process by producing antibodies for the cholera toxin. Current cholera vaccines target the cholera bacteria or both the bacteria and the toxin.
David Pascual, an expert in infectious diseases and immunology at the University of Florida, thinks that the MucoRice vaccine has huge promise. "I truly believe that the development of a food-based vaccine can be effective. CTB has a natural affinity for sampling cells in the gut to adhere, be processed, and then stimulate our immune system, he says. "In addition to vaccinating the gut, MucoRice has the potential to touch other mucosal surfaces in the mouth, which can help generate an immune response locally in the mouth and distally in the gut."
Cost Effectiveness
Kiyono says the MucoRice vaccine is much cheaper to produce than a traditional vaccine. Current vaccines need expensive bioreactors to grow cell cultures under very controlled, sterile conditions. This makes them expensive to manufacture, as different types of cell cultures need to be grown in separate buildings to avoid any chance of contamination. MucoRice doesn't require such an expensive manufacturing process because the rice plants themselves act as bioreactors.
The MucoRice vaccine also doesn't require the high cost of cold storage. It can be stored at room temperature for up to three years unlike traditional vaccines. "Plant-based vaccine development platforms present an exciting tool to reduce vaccine manufacturing costs, expand vaccine shelf life, and remove refrigeration requirements, all of which are factors that can limit vaccine supply and accessibility," Breakwell says.
Kathleen Hefferon, a microbiologist at Cornell University agrees. "It is much less expensive than a traditional vaccine, by a long shot," she says. "The fact that it is made in rice means the vaccine can be stored for long periods on the shelf, without losing its activity."
A plant-based vaccine may even be able to address vaccine hesitancy, which has become a growing problem in recent years. Hefferon suggests that "using well-known food plants may serve to reduce the anxiety of some vaccine hesitant people."
Challenges of Plant Vaccines
Despite their advantages, no plant-based vaccines have been commercialized for human use. There are a number of reasons for this, ranging from the potential for too much variation in plants to the lack of facilities large enough to grow crops that comply with good manufacturing practices. Several plant vaccines for diseases like HIV and COVID-19 are in development, but they're still in early stages.
In developing the MucoRice vaccine, scientists at the University of Tokyo have tried to overcome some of the problems with plant vaccines. They've created a closed facility where they can grow rice plants directly in nutrient-rich water rather than soil. This ensures they can grow crops all year round in a space that satisfies regulations. There's also less chance for variation since the environment is tightly controlled.
Clinical Trials and Beyond
After successfully growing rice plants containing the vaccine, the team carried out their first clinical trial. It was completed early this year. Thirty participants received a placebo and 30 received the vaccine. They were all Japanese men between the ages of 20 and 40 years old. 60 percent produced antibodies against the cholera toxin with no side effects. It was a promising result. However, there are still some issues Kiyono's team need to address.
The vaccine may not provide enough protection on its own. The antigen in any vaccine is the substance it contains to induce an immune response. For the MucoRice vaccine, the antigen is not the cholera bacteria itself but the cholera toxin the bacteria produces.
"The development of the antigen in rice is innovative," says David Sack, a professor at John Hopkins University and expert in cholera vaccine development. "But antibodies against only the toxin have not been very protective. The major protective antigen is thought to be the LPS." LPS, or lipopolysaccharide, is a component of the outer wall of the cholera bacteria that plays an important role in eliciting an immune response.
The Japanese team is considering getting the rice to also express the O antigen, a core part of the LPS. Further investigation and clinical trials will look into improving the vaccine's efficacy.
Beyond cholera, Kiyono hopes that the vaccine platform could one day be used to make cost-effective vaccines for other pathogens, such as norovirus or coronavirus.
"We believe the MucoRice system may become a new generation of vaccine production, storage, and delivery system."
Dana Lewis, pictured in Mount Vernon in 2017, worked with her engineer husband to design an artificial pancreas system to manage her type 1 diabetes.
For years, a continuous glucose monitor would beep at night if Dana Lewis' blood sugar measured too high or too low. At age 14, she was diagnosed with type 1 diabetes, an autoimmune disease that destroys insulin-producing cells in the pancreas.
The FDA just issued its first warning to the DIY diabetic community, after one patient suffered an accidental insulin overdose.
But being a sound sleeper, the Seattle-based independent researcher, now 30, feared not waking up. That concerned her most when she would run, after which her glucose dropped overnight. Now, she rarely needs a rousing reminder to alert her to out-of-range blood glucose levels.
That's because Lewis and her husband, Scott Leibrand, a network engineer, developed an artificial pancreas system—an algorithm that calculates adjustments to insulin delivery based on data from the continuous glucose monitor and her insulin pump. When the monitor gives a reading, she no longer needs to press a button. The algorithm tells the pump how much insulin to release while she's sleeping.
"Most of the time, it's preventing the frequent occurrences of high or low blood sugars automatically," Lewis explains.
Like other do-it-yourself device innovations, home-designed artificial pancreas systems are not approved by the Food and Drug Administration, so individual users assume any associated risks. Experts recommend that patients consult their doctor before adopting a new self-monitoring approach and to keep the clinician apprised of their progress.
DIY closed-loop systems can be uniquely challenging, according to the FDA. Patients may not fully comprehend how the devices are intended to work or they may fail to recognize the limitations. The systems have not been evaluated under quality control measures and pose risks of inappropriate dosing from the automated algorithm or potential incompatibility with a patient's other medications, says Stephanie Caccomo, an FDA spokeswoman.
Earlier this month, in fact, the FDA issued its first warning to the DIY diabetic community, which includes thousands of users, after one patient suffered an accidental insulin overdose.
Patients who built their own systems from scratch may be more well-versed in the operations, while those who are implementing unapproved designs created by others are less likely to be familiar with their intricacies, she says.
"Malfunctions or misuse of automated-insulin delivery systems can lead to acute complications of hypo- and hyperglycemia that may result in serious injury or death," Caccomo cautions. "FDA provides independent review of complex systems to assess the safety of these nontransparent devices, so that users do not have to be software/hardware designers to get the medical devices they need."
Only one hybrid closed-loop technology—the MiniMed 670G System from Minneapolis-based Medtronic—has been FDA-approved for type 1 use since September 2016. The term "hybrid" indicates that the system is not a fully automatic closed loop; it still requires minimal input from patients, including the need to enter mealtime carbohydrates, manage insulin dosage recommendations, and periodically calibrate the sensor.
Meanwhile, some tech-savvy people with type 1 diabetes have opted to design their own systems. About one-third of the DIY diabetes loopers are children whose parents have built them a closed system, according to Lewis' website.
Lewis began developing her system in 2014, well before Medtronic's device hit the market. "The choice to wait is not a luxury," she says, noting that "diabetes is inherently dangerous," whether an individual relies on a device to inject insulin or administers it with a syringe.
Hybrid closed-loop insulin delivery improves glucose control while decreasing the risk of low blood sugar in patients of various ages with less than optimally controlled type 1 diabetes, according to a study published in The Lancet last October. The multi-center randomized trial, conducted in the United Kingdom and the United States, spanned 12 weeks and included adults, adolescents, and children aged 6 years and older.
"We have compelling data attesting to the benefits of closed-loop systems," says Daniel Finan, research director at JDRF (formerly the Juvenile Diabetes Research Foundation) in New York, a global organization funding the study.
Medtronic's system costs between $6,000 and $9,000. However, end-user pricing varies based on an individual's health plan. It is covered by most insurers, according to the device manufacturer.
To give users more choice, in 2017 JDRF launched the Open Protocol Automated Insulin Delivery Systems initiative to collaborate with the FDA and experts in the do-it-yourself arena. The organization hopes to "forge a new regulatory paradigm," Finan says.
As diabetes management becomes more user-controlled, there is a need for better coordination. "We've had insulin pumps for a very long time, but having sensors that can detect blood sugars in real time is still a very new phenomenon," says Leslie Lam, interim chief in the division of pediatric endocrinology and diabetes at The Children's Hospital at Montefiore in the Bronx, N.Y.
"There's a lag in the integration of this technology," he adds. Innovators are indeed working to bring new products to market, "but on the consumer side, people want that to be here now instead of a year or two later."
The devices aren't foolproof, and mishaps can occur even with very accurate systems. For this reason, there is some reluctance to advocate for universal use in children with type 1 diabetes. Supervision by a parent, school nurse, and sometimes a coach would be a prudent precaution, Lam says.
People engage in "this work because they are either curious about it themselves or not getting the care they need from the health care system, or both."
Remaining aware of blood sugar levels and having a backup plan are essential. "People still need to know how to give injections the old-school way," he says.
To ensure readings are correct on Medtronic's device, users should check their blood sugar with traditional finger pricking at least five or six times per day—before every meal and whenever directed by the system, notes Elena Toschi, an endocrinologist and director of the Young Adult Clinic at Joslin Diabetes Center, an affiliate of Harvard Medical School.
"There can be pump failure and cross-talking failure," she cautions, urging patients not to stop being vigilant because they are using an automated device. "This is still something that can happen; it doesn't eliminate that."
While do-it-yourself devices help promote autonomy and offer convenience, the lack of clinical trial data makes it difficult for clinicians and patients to assess risks versus benefits, says Lisa Eckenwiler, an associate professor in the departments of philosophy and health administration and policy at George Mason University in Fairfax, Va.
"What are the responsibilities of physicians in that context to advise patients?" she questions. Some clinicians foresee the possibility that "down the road, if things go awry" with disease management, that could place them "in a moral quandary."
Whether it's controlling diabetes, obesity, heart disease or asthma, emerging technologies are having a major influence on individuals' abilities to stay on top of their health, says Camille Nebeker, an assistant professor in the School of Medicine at the University of California, San Diego, and founder and director of its Research Center for Optimal Data Ethics.
People engage in "this work because they are either curious about it themselves or not getting the care they need from the health care system, or both," she says. In "citizen science communities," they may partner in participant-led research while gaining access to scientific and technical expertise. Others "may go it alone in solo self-tracking studies or developing do-it-yourself technologies," which raises concerns about whether they are carefully considering potential risks and weighing them against possible benefits.
Dana Lewis admits that "using do-it-yourself systems might not be for everyone. But the advances made in the do-it-yourself community show what's possible for future commercial developments, and give a lot of hope for improved quality of life for those of us living with type 1 diabetes."
The Grim Reaper Can Now Compost Your Body
An artist's rendering of a future Recompose facility in Washington state, with reusable modular vessels that convert human remains to soil.
Ultra-green Seattle isn't just getting serious about living eco-friendly, but dying that way, too. As of this week, Washington is officially the first state to allow citizens to compost their own dead bodies.
Their bodies, including bones, were converted into clean, odorless soil free of harmful pathogens.
The Lowdown
Keep in mind this doesn't mean dumping your relative in a nearby river. Scientists and organizations have ways to help Mother Nature process the remains. For instance, the late actor Luke Perry reportedly was buried in a mushroom suit. Perry's garment is completely biodegradable and the attached microorganisms help the decomposition process cleanly and efficiently.
A biodegradable burial requires only a fraction of the energy used for cremation and can save a metric ton of CO2. The body decomposes in about a month. Besides a mushroom suit, another option coming down the pike in Washington state is to have your body converted directly into soil in a special facility.
A pilot study last summer by a public benefit corporation called Recompose signed up six terminally ill people who donated their remains for such research. Their bodies, including bones, were converted into clean, odorless soil free of harmful pathogens. That soil—about a cubic yard per person--could then be returned after 30 days to the subjects' families.
Green burials open the door to creative memorials. A tree or garden could be planted with your soil. This method provides a climate-friendly alternative to traditional funerals, circumventing toxic embalming fluid, expensive casket materials and other ecological overhead. The fertile soil could also be given to conservationist organizations.
Next Up
The new legislation in Washington will take effect May 1, 2020. The Pacific Northwest state has one of the highest cremation rates in the nation at 78 percent, only second to Nevada. Rising climate change and increased interest in death management will only speed this discussion to the forefront in other states.
A biodegradable burial requires only a fraction of the energy used for cremation and can save a metric ton of CO2.
It's also worth noting Perry wasn't buried in Washington State, but in Tennessee. It is unknown where exactly he was laid to rest, nor if it was done under a legal precedent or special exception.
According to the Green Burial Council, each state varies on how and where you can bury someone. Home burials are usually legal, but to do so requires establishing an official cemetery area on the property. How someone is buried has even more dynamic legislation. There will be new discussions about how neighbors contend with nearby decomposing bodies, legal limitations to private burial techniques, and other issues never addressed before in modern mainstream America.
Open Questions
It's unclear if green burials will be commonplace for those with less financial means or access. Mushroom suits average a couple thousand dollars, making them more expensive than a low-end casket. There are also the less obvious expenses, including designating the place of burial, and getting proper burial support and guidance. In short, you likely won't go to the local funeral home and be taken care of properly. It is still experimental.
As for "natural organic reduction" (converting human remains to soil in reusable modular vessels), Recompose is still figuring out its pricing for Washington residents, but expects the service to cost more than cremation and less than a conventional burial.
For now, environmentally sustainable death care may be comparable to vegetarianism in the 1970s or solar paneling in the 1980s: A discussion among urbanites and upwardly-mobile financial classes, but not yet an accessible option for the average American. It's not a coincidence that the new Washington law received support in Seattle, one of the top 10 wealthiest cities in America. A similar push may take off in less affluent areas if ecological concerns drive a demand for affordable green burial options.
Until then, your neighborhood mortician still has the death business on lock.