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."
The Secrets of a Long Life from the U.S.’s Top Longevity Hot Spot
Summit County resident Gloria Breigenzer, 75, does a yoga headstand in the Rocky Mountains while her horse looks on.
People are living longer in the world's richest countries, according to a recent Pew Report. Certain areas, in particular, have drawn the attention of researchers who study longevity because in those places, living to 100 is not unusual.
"If you want to live longer, shape your environment."
At 8000 feet up, Summit County, Colorado is a longevity hotspot. Surrounded by mountains that soar to more than 14,000 feet, the population of nearly 31,000 brags the highest expected lifespan in the United States, at 86.83 years. For comparison, the average life expectancy in the U.S. is 78.6 years.
So, what is it about living in Summit County that has brought about this high honor?
Despite popular belief, it's not about genes. Only about "20-30 percent of longevity can be predicted by genetics," longevity researcher Howard S. Friedman wrote in an email exchange. Friedman, a professor at the University of California at Riverside, co-authored a book about a famous study that followed participants for eight decades to learn what traits and factors contribute to a long life.
"About half is behavioral (including environmental)," Friedman says. "The rest is random (chance)." His longevity research is based on work that began in 1921 by Stanford University psychologist Lewis Terman. To discern the keys to longevity, Friedman and colleagues spent 20 years looking back at the lives led by the 1500 "gifted" 11-year old boys and girls who were born in 1910 and participated in Terman's study.
"We found that ambition, perseverance, and high motivation … predicted not only success but also longevity: Stressful job and hard work, long life!" Friedman says.
Longevity expert Dan Buettner agrees that an individual's environment is key. Buettner studies what he calls Blue Zones, where people "naturally live longer." But, unlike the five Blue Zones in the world -- Okinawa, Japan; Sardinia, Italy; Nicoya, Costa Rica; Ikaria, Greece; and Loma Linda, California — the majority of the Summit County population chose to move to the mountain towns that make up the region. Because Buettner believes that people can be taught to live longer, he sees Summit County as an instructive locale.
Like the Blue Zones, people in Summit County "do not pursue healthy lifestyles; [rather] it ensues," he says. "Blue Zones have the benefit of traditional patterns of eating and traditional rhythms of life. So they tend to be places where people walk to work, to a friend's house … [and] Blue Zone people eat the right food -- not because they have better individual responsibility or discipline; they simply live in an environment where beans, greens, nuts and grains are cheapest and most accessible."
"If you want to live longer," Buettner says, "shape your environment."
But an individual's environment can be affected by a number of factors, including socioeconomics, race, quality of and access to health care, as well as behavioral and metabolic risks. While the residents of Summit County smoke less and exercise more than those in regions with shorter life spans, they also have higher incomes and levels of education and lower unemployment.
"The healthiest individuals in The Longevity Project…lived meaningful, committed lives. They worked hard and played hard."
Gloria Breigenzer moved to Summit County 20 years ago with her husband. "We wanted to ski and ride horses up in the mountains," says Breigenzer. The 75-year-old still works part time as a hair dresser, goes to the gym every day, lifts weights and does yoga.
"I don't know why people don't want to get up and go out and work out and do stuff. I do," says the grandmother, who also exercises her rescue horse five days a week and for the past 15 years has done swing, country two step, and jazz dance in a group with her 77-year-old husband. She's also taking kiteboarding lessons and for the past two years has spent every afternoon studying Spanish.
Pete and Judy Rubin, both 65, retired to Summit County nearly two years ago from Cleveland. In Colorado, "socializing doesn't revolve around food," says Pete. "In Cleveland it always did…[Being outside] in summer or in winter is just easy. Skiing, on a bike, taking a hike, mowing the lawn, looking at a mountain instead of having someone else do it."
The Summit County approach resonates for researcher Friedman, who says that it's the "constellations of habits and patterns of living," that stood out most to him in his study. "Throw away your lists...The healthiest individuals in The Longevity Project…lived meaningful, committed lives. They worked hard and played hard. They were very persistent and responsible, and they were dedicated to things and people beyond themselves."
The following are some of the common denominators found in populations that live longer, including those who live in Summit County:
Plant-based diet: "Eat meat, no more than 5 times a month … [and] 95 percent of all the calories you take in should be whole plant-based foods," says Buettner.
Know your purpose: Buettner found that having and understanding your sense of purpose is worth up to seven years of extra life expectancy.
Have friendships: "You should have three to five friends who are healthy themselves who you can call on a bad day and they'll care," says Buettner.
Be on the move: Populations in zones where there is higher longevity "move naturally" as part of their day. It's not about diets. "No diet in the history of the world has worked for more than 5 percent of people after two years," says Buettner.
Relieve stress: "You should have some daily practices that help you downshift," says Buettner. It "could be taking naps, or meditation practice, or a habit of praying or a habit of doing happy hours."
Employ a family first rule: "Successful centenarians put their families first," explains Buettner. "And that means keeping your aging parents nearby, being seriously invested in your partner and if you have kids, you make them a priority."
It's these "key patterns of living [that] tend to make you both healthier and happier," says Friedman. "And health and happiness often then mutually reinforce each other."
Here's What It Looks Like to Seek Therapy for Climate Change Anxiety
Treatment for climate change anxiety looks different from treating generalized anxiety in that the concerns have a legitimate basis, therapists say.
Three months after Gretchen bought a house in Grass Valley, California, the most destructive and fatal wildfire in the state's history ravaged the towns about 40 miles northwest of her.
"For a long time, I kept on having this vision of what my town will look like if one of those firestorms happens, and I felt like I needed to work on that."
The Camp Fire of November 2018 was noteworthy not just because of its damaging scale but because of what started it all: a spark from a faulty transmission line owned by the Pacific Gas & Electric Company, which services nearly two-thirds of California.
PG&E reacted by announcing almost a year later that in advance of days with a high fire risk, it would proactively institute power outages in 17 counties throughout the northern part of the state, including the one where Gretchen lives. The binary options seemed to be: cause another fire or intermittently plunge tens of thousands of people into literal and figurative darkness, impacting emergency services, health, food, internet, gas, and any other electrified necessity or convenience of modern life.
This summer, in between the end of the Camp Fire and the beginning of the blackouts, Gretchen, who asked to keep her last name private, decided it was time to seek counseling for climate-related anxiety.
"That was a very traumatic experience to go through," Gretchen, 39, says, describing what it was like to have recently settled in this increasingly fire-prone part of her home state, and later witnessing a colleague flee California altogether after his own home burned down and he couldn't afford to stay. "For a long time, I kept on having this vision of what my town will look like if one of those firestorms happens, and I felt like I needed to work on that."
While research on climate anxiety—or, more broadly, the effects of climate change on mental health—has been slowly but surely piling up, the actual experience of diagnosing and treating it is less well-documented in both media and academia. An ongoing Yale University study of American perceptions of climate change shows an increasing proportion of concern: In 2018, 29 percent of 1,114 survey respondents said they were "very worried" about climate change, up from 16 percent in 2008. But there are no parallel large-scale studies of whether a similar proportion of people are in therapy for climate change-related mental health issues.
That might be because many would-be clients don't yet realize that this is a valid concern for which to seek out professional support. It could also be because there are no definitive or unifying resources for therapists who are counseling people on the topic. Climate anxiety is notably absent by name from the Diagnostic and Statistical Manual of Mental Disorders (DSM), the psychological gospel for everyone from clinicians to lawmakers. The manual was last updated in 2012 (and published in 2013), just when the first documents of climate anxiety were beginning to crop up.
A small 2013 study surveyed college students in the U.S. and Europe to try and answer the question: Is habitually worrying about the environment a mental health concern if it's a response to a real threat? The study concluded: "...those who habitually worry about the ecology are not only lacking in any psychopathology, but demonstrate a constructive and adaptive response to a serious problem." In other words, worrying about a concrete external concern like the state of the environment is on a different plane than habitually worrying about an internal concern, like feelings of inadequacy. Therapy may still help with the former, but the diagnostic framework could ultimately look different than what is typically used in generalized anxiety.
For now, the best resource for therapists counseling patients battling what is sometimes dubbed "ecoanxiety" is a 70-page booklet called "Mental Health and Our Changing Climate: Impacts, Implications, and Guidance," whose publication was co-sponsored by the American Psychological Association, which publishes the DSM. It's been through two editions already, the first in 2014 and the second in 2017.
"It's not clear to me that [climate anxiety] would merit its own diagnosis, at least at this point," says Susan Clayton, who was the lead author on the 2017 edition and who studies this area at The College of Wooster, but doesn't counsel people directly. However, she says, "I do think that there are some differences [from generalized anxiety], and one of the important differences is, of course, that there's some realism here."
Clayton says that group therapy may be a particularly useful way to affirm for people that they're not the only one experiencing climate anxiety, especially in communities where it might be taboo to not only affirm the existence of climate change but to be openly affected by it.
On drawing therapeutic inspiration from historical examples of other global dangers—such as the widespread fear of nuclear threat during the Cold War—Clayton says: "That was such a different time and they were thinking differently about mental health, but I think in many ways the fear is very similar. It's not like worrying about your finances, it's worrying about the end of the world. So that sort of existential component, and the fact that it's shared, both are very similar here."
There are precedents that therapists can refer to for guidance on helping clients managing climate anxiety, like the approaches used to support people dealing with a terminal illness or battling systemic racism. Such treatments need to stay rooted in the reality of the trigger.
"You don't want to say to them, 'That's not a real thing,'" Clayton explains. "So I think of [climate anxiety] like that. It does mean that the therapeutic focus is not going to be on trying to get people to be reasonable," which is to say that their anxiety is not inherently unreasonable.
"I think it is important to recognize that the anxieties have a legitimate basis," she adds.
"I feel more comfortable now being prepared, being prudent, but not dwelling on it all the time."
Gretchen's reality is now one of adapting to living an off-the-grid lifestyle that she didn't intentionally sign up for. She puts gas in her car in advance of blackouts, and waits to see week-by-week if the school where she teaches second and third grade, in the foothills of Tahoe National Park, will be closed. Her union has yet to figure out how this stop-and-go schedule will affect her salary; she has to keep rescheduling parent-teacher conferences; and she no longer knows when the last day of school will be—existing summer plans for her personal life be damned. Even her interview for this story was affected by this instability.
While trying to schedule a time to talk, she wrote, "Speaking of climate change, I may not have work the rest of the week due to PG&E power outages. If so I will have a very flexible schedule." Later, she suddenly had to decline. "As it turns out, the power's not going out. I will be at work."
In therapy sessions, she works with her counselor to focus on preparedness, where possible, and to specifically frame that preparedness as a source of regaining some of the stability she's lost rather than a sign of imminent trouble. That nuance became necessary after a training at work had the opposite effect.
"We've gone through scenarios [where] if a firestorm happens and we don't have time to evacuate, we have to gather all the children into the cafeteria and fend off the flames ourselves with help from the fire department, and keep them alive if we can't get out in time," she says. "After that day, or that training, that really scared me."
Her therapist uses a type of psychotherapy called eye movement desensitization and reprocessing (EMDR) to help Gretchen move away from traumatizing images, such as picturing her town on fire, while emphasizing what it is that she can control, such as making sure her car has a full tank, in case she needs to evacuate. EMDR has been shown to help people with post-traumatic stress disorder (PTSD) and the World Health Organization offers practice guidelines around it.
"I feel more comfortable now being prepared, being prudent, but not dwelling on it all the time," she says. "I feel a little less heightened anxiety and have stopped replaying [those images] in my mind."
Overall, the type of support Gretchen receives is based on pre-existing tools for managing other well-established mental health burdens like PTSD and generalized anxiety. Although no definitive, new practices have specifically emerged around climate anxiety on a comprehensive scale yet, Gretchen says she was nonetheless met with compassion when she first approached a therapist about the topical source of her anxiety, and doesn't feel that her care is lacking in any way.
"I don't know enough to know whether or how it should become its own diagnosis, but I feel like it's something that is still evolving. Down the road, as we see more populations having to move, more refugees, more real effects, that might change," she says. "For me, using the old tools in a new way has been effective at this point."
Gretchen hasn't yet explored with her therapist the more existential worries that climate change dredges up for her—worries about whether or not to have children, and if it was a mistake to settle down in Grass Valley. She's only been in therapy for her climate anxiety since the summer (although she has intermittently sought out professional mental health support for other reasons over the last eight years), and it will take time to get to these bigger issues, she says. She's not sure yet whether that part of her counseling will look different than what's she's done so far.
But she does wonder about the overall usefulness of pathologizing what, as Clayton said, are legitimate anxieties. She has the same question when it comes to providing mental health support for her students, many of whom live in poverty.
"Is it just putting a bandaid on something that is unfixable, or is unfair?" she ponders. But de-escalating the psychological toll that climate change can have on people is crucial to giving them back the energy to deal with the problem itself, not just their reaction to the problem. Clayton believes that engaging in climate activism can provide solace for the people who do have that energy.
"This is a social issue, and there's obviously lots and lots of climate activism," she says. "You might not be comfortable being politically active, but I think getting involved in some way, and addressing the issue, would help people feel much more empowered, and would help with the experience of climate anxiety."
"Remember that nature is not just a source of anxiety, it's also a source of replenishment and restoration."
As far as what shape this personal involvement takes, an increasingly vocal movement of people is calling for a refocus. They say the onus of reversing, or at least stymying, the situation should fall on the big businesses and governments that have been too slow to act, not on individual consumer actions, like buying sustainably made clothes, divesting from the meat and dairy industry, or driving an electric car.
But outside of formal therapy and even activism, however that looks, Clayton has another suggestion for combating climate anxiety, and it's one that is surprising in its simplicity: Go outside, and take stock of that which boldly continues to exist.
"People who are anxious about climate change, it's partly about the survival of the species, but it's partly about the sense that, 'Something I care about is being destroyed,'" she says. "Remember that nature is not just a source of anxiety, it's also a source of replenishment and restoration."