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 Friday Five Weekly Roundup in Health Research
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
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Here are the promising studies covered in this week's Friday Five:
- The right facial expression for your mental health
- Can virtual reality reduce pain?
- Lab made blood vessels
- Gene editing muscles to lower blood sugar
- A magic ingredient coming from exhaust vents
Many leaders at top companies are trying to get workers to return to the office. They say remote and hybrid work are bad for their employees’ mental well-being and lead to a sense of social isolation, meaninglessness, and lack of work-life boundaries, so we should just all go back to office-centric work.
One example is Google, where the company’s leadership is defending its requirement of mostly in-office work for all staff as necessary to protect social capital, meaning people’s connections to and trust in one another. That’s despite a survey of over 1,000 Google employees showing that two-thirds feel unhappy about being forced to work in the office three days per week. In internal meetings and public letters, many have threatened to leave, and some are already quitting to go to other companies with more flexible options.
Last month, GM rolled out a policy similar to Google’s, but had to backtrack because of intense employee opposition. The same is happening in some places outside of the U.S. For instance, three-fifths of all Chinese employers are refusing to offer permanent remote work options, according to a survey this year from The Paper.
For their claims that remote work hurts well-being, some of these office-centric traditionalists cite a number of prominent articles. For example, Arthur Brooks claimed in an essay that “aggravation from commuting is no match for the misery of loneliness, which can lead to depression, substance abuse, sedentary behavior, and relationship damage, among other ills.” An article in Forbes reported that over two-thirds of employees who work from home at least part of the time had trouble getting away from work at the end of the day. And Fast Company has a piece about how remote work can “exacerbate existing mental health issues” like depression and anxiety.
For his part, author Malcolm Gladwell has also championed a swift return to the office, saying there is a “core psychological truth, which is we want you to have a feeling of belonging and to feel necessary…I know it’s a hassle to come into the office, but if you’re just sitting in your pajamas in your bedroom, is that the work life you want to live?”
These arguments may sound logical to some, but they fly in the face of research and my own experience as a behavioral scientist and as a consultant to Fortune 500 companies. In these roles, I have seen the pitfalls of in-person work, which can be just as problematic, if not more so. Remote work is not without its own challenges, but I have helped 21 companies implement a series of simple steps to address them.
Research finds that remote work is actually better for you
The trouble with the articles described above - and claims by traditionalist business leaders and gurus - stems from a sneaky misdirection. They decry the negative impact of remote and hybrid work for wellbeing. Yet they gloss over the damage to wellbeing caused by the alternative, namely office-centric work.
It’s like comparing remote and hybrid work to a state of leisure. Sure, people would feel less isolated if they could hang out and have a beer with their friends instead of working. They could take care of their existing mental health issues if they could visit a therapist. But that’s not in the cards. What’s in the cards is office-centric work. That means the frustration of a long commute to the office, sitting at your desk in an often-uncomfortable and oppressive open office for at least 8 hours, having a sad desk lunch and unhealthy snacks, sometimes at an insanely expensive cost and, for making it through this series of insults, you’re rewarded with more frustration while commuting back home.
In a 2022 survey, the vast majority of respondents felt that working remotely improved their work-life balance. Much of that improvement stemmed from saving time due to not needing to commute and having a more flexible schedule.
So what happens when we compare apples to apples? That’s when we need to hear from the horse’s mouth: namely, surveys of employees themselves, who experienced both in-office work before the pandemic, and hybrid and remote work after COVID struck.
Consider a 2022 survey by Cisco of 28,000 full-time employees around the globe. Nearly 80 percent of respondents say that remote and hybrid work improved their overall well-being: that applies to 83 percent of Millennials, 82 percent of Gen Z, 76 percent of Gen Z, and 66 percent of Baby Boomers. The vast majority of respondents felt that working remotely improved their work-life balance.
Much of that improvement stemmed from saving time due to not needing to commute and having a more flexible schedule: 90 percent saved 4 to 8 hours or more per week. What did they do with that extra time? The top choice for almost half was spending more time with family, friends and pets, which certainly helped address the problem of isolation from the workplace. Indeed, three-quarters of them report that working from home improved their family relationships, and 51 percent strengthened their friendships. Twenty percent used the freed up hours for self-care.
Of the small number who report their work-life balance has not improved or even worsened, the number one reason is the difficulty of disconnecting from work, but 82 percent report that working from anywhere has made them happier. Over half say that remote work decreased their stress levels.
Other surveys back up Cisco’s findings. For example, a 2022 Future Forum survey compared knowledge workers who worked full-time in the office, in a hybrid modality, and fully remote. It found that full-time in-office workers felt the least satisfied with work-life balance, hybrid workers were in the middle, and fully remote workers felt most satisfied. The same distribution applied to questions about stress and anxiety. A mental health website called Tracking Happiness found in a 2022 survey of over 12,000 workers that fully remote employees report a happiness level about 20 percent greater than office-centric ones. Another survey by CNBC in June found that fully remote workers are more often very satisfied with their jobs than workers who are fully in-person.
Academic peer-reviewed research provides further support. Consider a 2022 study published in the International Journal of Environmental Research and Public Health of bank workers who worked on the same tasks of advising customers either remotely or in-person. It found that fully remote workers experienced higher meaningfulness, self-actualization, happiness, and commitment than in-person workers. Another study, published by the National Bureau of Economic Research, reported that hybrid workers, compared to office-centric ones, experienced higher satisfaction with work and had 35 percent more job retention.
What about the supposed burnout crisis associated with remote work? Indeed, burnout is a concern. A survey by Deloitte finds that 77 percent of workers experienced burnout at their current job. Gallup came up with a slightly lower number of 67 percent in its survey. But guess what? Both of those surveys are from 2018, long before the era of widespread remote work.
By contrast, in a Gallup survey in late 2021, 58 percent of respondents reported less burnout. An April 2021 McKinsey survey found burnout in 54 percent of Americans and 49 percent globally. A September 2021 survey by The Hartford reported 61 percent burnout. Arguably, the increase in full or part-time remote opportunities during the pandemic helped to address feelings of burnout, rather than increasing them. Indeed, that finding aligns with the earlier surveys and peer-reviewed research suggesting remote and hybrid work improves wellbeing.
Remote work isn’t perfect – here’s how to fix its shortcomings
Still, burnout is a real problem for hybrid and remote workers, as it is for in-office workers. Employers need to offer mental health benefits with online options to help employees address these challenges, regardless of where they’re working.
Moreover, while they’re better overall for wellbeing, remote and hybrid work arrangements do have specific disadvantages around work-life separation. To address work-life issues, I advise my clients who I helped make the transition to hybrid and remote work to establish norms and policies that focus on clear expectations and setting boundaries.
For working at home and collaborating with others, there’s sometimes an unhealthy expectation that once you start your workday in your home office chair, and that you’ll work continuously while sitting there.
Some people expect their Slack or Microsoft Teams messages to be answered within an hour, while others check Slack once a day. Some believe email requires a response within three hours, and others feel three days is fine. As a result of such uncertainty and lack of clarity about what’s appropriate, too many people feel uncomfortable disconnecting and not replying to messages or doing work tasks after hours. That might stem from a fear of not meeting their boss’s expectations or not wanting to let their colleagues down.
To solve this problem, companies need to establish and incentivize clear expectations and boundaries. They should develop policies and norms around response times for different channels of communication. They also need to clarify work-life boundaries – for example, the frequency and types of unusual circumstances that will require employees to work outside of regular hours.
Moreover, for working at home and collaborating with others, there’s sometimes an unhealthy expectation that once you start your workday in your home office chair, and that you’ll work continuously while sitting there (except for your lunch break). That’s not how things work in the office, which has physical and mental breaks built in throughout the day. You took 5-10 minutes to walk from one meeting to another, or you went to get your copies from the printer and chatted with a coworker on the way.
Those and similar physical and mental breaks, research shows, decrease burnout, improve productivity, and reduce mistakes. That’s why companies should strongly encourage employees to take at least a 10-minute break every hour during remote work. At least half of those breaks should involve physical activity, such as stretching or walking around, to counteract the dangerous effects of prolonged sitting. Other breaks should be restorative mental activities, such as meditation, brief naps, walking outdoors, or whatever else feels restorative to you.
To facilitate such breaks, my client organizations such as the University of Southern California’s Information Sciences Institute shortened hour-long meetings to 50 minutes and half-hour meetings to 25 minutes, to give everyone – both in-person and remote workers – a mental and physical break and transition time.
Very few people will be reluctant to have shorter meetings. After that works out, move to other aspects of setting boundaries and expectations. Doing so will require helping team members get on the same page and reduce conflicts and tensions. By setting clear expectations, you’ll address the biggest challenge for wellbeing for remote and hybrid work: establishing clear work-life boundaries.