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 Nation’s Science and Health Agencies Face a Credibility Crisis: Can Their Reputations Be Restored?
Morale at federal science agencies -- and public trust in their guidance -- is at a concerning low right now.
This article is part of the magazine, "The Future of Science In America: The Election Issue," co-published by LeapsMag, the Aspen Institute Science & Society Program, and GOOD.
It didn't have to be this way. More than 200,000 Americans dead, seven million infected, with numbers continuing to climb, an economy in shambles with millions out of work, hundreds of thousands of small businesses crushed with most of the country still under lockdown. And all with no end in sight. This catastrophic result is due in large part to the willful disregard of scientific evidence and of muzzling policy experts by the Trump White House, which has spent its entire time in office attacking science.
One of the few weapons we had to combat the spread of Covid-19—wearing face masks—has been politicized by the President, who transformed this simple public health precaution into a first amendment issue to rally his base. Dedicated public health officials like Dr. Anthony Fauci, the highly respected director of the National Institute of Allergies and Infectious Diseases, have received death threats, which have prompted many of them around the country to resign.
Over the summer, the Trump White House pressured the Centers for Disease Control, which is normally in charge of fighting epidemics, to downplay COVID risks among young people and encourage schools to reopen. And in late September, the CDC was forced to pull federal teams who were going door-to-door doing testing surveys in Minnesota because of multiple incidents of threats and abuse. This list goes on and on.
Still, while the Trump administration's COVID failures are the most visible—and deadly—the nation's entire federal science infrastructure has been undermined in ways large and small.
The White House has steadily slashed monies for science—the 2021 budget cuts funding by 10–30% or more for crucial agencies like National Oceanic and Atmospheric Administration (NOAA) and the Environmental Protection Agency (EPA)—and has gutted health and science agencies across the board, including key agencies of the Department of Energy and the Interior, especially in divisions that deal with issues they oppose ideologically like climate change.
Even farmers can't get reliable information about how climate change affects planting seasons because the White House moved the entire staff at the U.S. Department of Agriculture agency who does this research, relocating them from Maryland to Kansas City, Missouri. Many of these scientists couldn't uproot their families and sell their homes, so the division has had to pretty much start over from scratch with a skeleton crew.
More than 1,600 federal scientists left government in the first two years of the Trump Administration, according to data compiled by the Washington Post, and one-fifth of top positions in science are vacant, depriving agencies of the expertise they need to fulfill their vital functions. Industry executives and lobbyists have been installed as gatekeepers—HHS Secretary Alex Azar was previously president of Eli Lilly, and three climate change deniers were appointed to key posts at the National Oceanic and Atmospheric Administration, to cite just a couple of examples. Trump-appointed officials have sidelined, bullied, or even vilified those who dare to speak out, which chills the rigorous debate that is the essential to sound, independent science.
"The CDC needs to be able to speak regularly to the American people to explain what it knows and how it knows it."
Linda Birnbaum knows firsthand what it's like to become a target. The microbiologist recently retired after more than a decade as the director of the National Institute of Environmental Health Sciences, which is the world's largest environmental health organization and the greatest funder of environmental health and toxicology research, a position that often put her agency at odds with the chemical and fossil fuel industry. There was an attempt to get her fired, she says, "because I had the nerve to write that science should be used in making policy. The chemical industry really went after me, and my last two years were not so much fun under this administration. I'd like to believe it was because I was making a difference—if I wasn't, they wouldn't care."
Little wonder that morale at federal agencies is low. "We're very frustrated," says Dr. William Schaffner, a veteran infectious disease specialist and a professor of medicine at the Vanderbilt University School of Medicine in Nashville. "My colleagues within these agencies, the CDC rank and file, are keeping their heads down doing the best they can, and they hope to weather this storm."
The cruel irony is that the United States was once a beacon of scientific innovation. In the heady post World War II years, while Europe lay in ruins, the successful development of penicillin and the atomic bomb—which Americans believed helped vanquish the Axis powers—unleashed a gusher of public money into research, launching an unprecedented era of achievement in American science. Scientists conquered polio, deciphered the genetic code, harnessed the power of the atom, invented lasers, transistors, microchips and computers, sent missions beyond Mars, and landed men on the moon. A once-inconsequential hygiene laboratory was transformed into the colossus the National Institutes of Health has become, which remains today the world's flagship medical research center, unrivaled in size and scope.
At the same time, a tiny public health agency headquartered in Atlanta, which had been in charge of eradicating the malaria outbreaks that plagued impoverished rural areas in the Deep South until the late 1940s, evolved into the Centers for Disease Control and Prevention. The CDC became the world's leader in fighting disease outbreaks, and the agency's crack team of epidemiologists—members of the vaunted Epidemic Intelligence Service—were routinely dispatched to battle global outbreaks of contagions such as Ebola and malaria and help lead the vaccination campaigns to eradicate killers like polio and small pox that have saved millions of lives.
What will it take to rebuild our federal science infrastructure and restore not only the public's confidence but the respect of the world's scientific community? There are some hopeful signs that there is pushback against the current national leadership, and non-profit watchdog groups like the Union of Concerned Scientists have mapped out comprehensive game plans to restore public trust and the integrity of science.
These include methods of protecting science from political manipulation; restoring the oversight role of independent federal advisory committees, whose numbers were decimated by recent executive orders; strengthening scientific agencies that have been starved by budget cuts and staff attrition; and supporting whistleblower protections and allowing scientists to do their jobs without political meddling to restore integrity to the process. And this isn't just a problem at the CDC. A survey of 1,600 EPA scientists revealed that more than half had been victims of political interference and were pressured to skew their findings, according to research released in April by the Union of Concerned Scientists.
"Federal agencies are staffed by dedicated professionals," says Andrew Rosenberg, director of the Center for Science and Democracy at the Union of Concerned Scientists and a former fisheries biologist for NOAA. "Their job is not to serve the president but the public interest. Inspector generals are continuing to do what they're supposed to, but their findings are not being adhered to. But they need to hold agencies accountable. If an agency has not met its mission or engaged in misconduct, there needs to be real consequences."
On other fronts, last month nine vaccine makers, including Sanofi, Pfizer, and AstraZeneca, took the unprecedented stop of announcing that their COVID-19 vaccines would be thoroughly vetted before they were released. In their implicit refusal to bow to political pressure from the White House to have a vaccine available before the election, their goal was to restore public confidence in vaccine safety, and ensure that enough Americans would consent to have the shot when it was eventually approved so that we'd reach the long-sought holy grail of herd immunity.
"That's why it's really important that all of the decisions need to be made with complete transparency and not taking shortcuts," says Dr. Tom Frieden, president and CEO of Resolve to Save Lives and former director of the CDC during the H1N1, Ebola, and Zika emergencies. "A vaccine is our most important tool, and we can't break that tool by meddling in the science approval process."
In late September, Senate Democrats introduced a new bill to halt political meddling in public health initiatives by the White House. Called Science and Transparency Over Politics Act (STOP), the legislation would create an independent task force to investigate political interference in the federal response to the coronavirus pandemic. "The Trump administration is still pushing the president's political priorities rather than following the science to defeat this virus," Senate Minority Leader Chuck Schumer said in a press release.
To effectively bring the pandemic under control and restore public confidence, the CDC must assume the leadership role in fighting COVID-19. During previous outbreaks, the top federal infectious disease specialists like Drs. Fauci and Frieden would have daily press briefings, and these need to resume. "The CDC needs to be able to speak regularly to the American people to explain what it knows and how it knows it," says Frieden, who cautions that a vaccine won't be a magic bullet. "There is no one thing that is going to make this virus go away. We need to continue to limit indoor exposures, wear masks, and do strategic testing, isolation, and quarantine. We need a comprehensive approach, and not just a vaccine."
We must also appoint competent and trustworthy leaders, says Rosenberg of the Union of Concerned Scientists. Top posts in too many science agencies are now filled by former industry executives and lobbyists with a built-in bias, as well as people lacking relevant scientific experience, many of whom were never properly vetted because of the current administration's penchant for bypassing Congress and appointing "acting" officials. "We've got great career people who have hung in, but in so much of the federal government, they just put in 'acting' people," says Linda Birnbaum. "They need to bring in better, qualified senior leadership."
Open positions need to be filled, too. Federal science agencies have been seriously crippled by staffing attrition, and the Trump Administration instituted a hiring freeze when it first came in. Staffing levels remain at least ten percent down from previous levels, says Birnbaum and in many agencies, like the EPA, "everything has come to a screeching halt, making it difficult to get anything done."
But in the meantime, the critical first step may be at the ballot box in November. Even Scientific American, the esteemed consumer science publication, for the first time in its 175-year history felt "compelled" to endorse a presidential candidate, Joe Biden, because of the enormity of the damage they say Donald Trump has inflicted on scientists, their legal protections, and on the federal science agencies.
"If the current administration continues, the national political leadership will be emboldened and will be even more assertive of their executive prerogatives and less concerned about traditional niceties, leading to further erosion of the activities of many federal agencies," says Vanderbilt's William Schaffner. "But the reality is, if the team is losing, you change the coach. Then agencies really have to buckle down because it will take some time to restore their hard-earned reputations."
[Editor's Note: To read other articles in this special magazine issue, visit the beautifully designed e-reader version.]
Announcing "The Future of Science in America: The Election Issue"
This special magazine explores what's at stake for science & policy over the next four years.
As reviewed in The Washington Post, "Tomorrow's challenges in science and politics: Magazine offers in-depth takes on these U.S. issues":
"Is it time for a new way to help make adults more science-literate? What should the next president know about science? Could science help strengthen American democracy? "The Future of Science in America: The Election Issue" has answers. The free, online magazine is packed with interesting takes on how science can serve the common good. And just in time. This year has challenged leaders, researchers and the public with thorny scientific questions, from the coronavirus pandemic to widespread misinformation on scientific issues. The magazine is a collaboration of the Aspen Institute, a think tank that brings together a variety of public figures and private individuals to tackle thorny social issues, the digital science magazine Leapsmag and GOOD, a social impact company. It's packed with 15 in-depth articles about science with a view toward our campaign year."
The Future of Science in America: The Election Issue offers wide-ranging perspectives on challenges and opportunities for science as we elect our next national and local leaders. The fast-striking COVID-19 pandemic and the more slowly moving pandemic of climate change have brought into sharp focus how reliant we will be on science and public policy to work together to rescue us from crisis. Doing so will require cooperation between both political parties, as well as significant public trust in science as a beacon to light the path forward.
In spite of its unfortunate emergence as a flash point between two warring parties, we believe that science is the driving force for universal progress. No endeavor is more noble than the quest to rigorously understand our world and apply that knowledge to further human flourishing. This magazine aspires to promote roadmaps for science as a tool for health, a vehicle for progress, and a unifier of our nation.
This special issue is a collaboration among LeapsMag, the Aspen Institute Science & Society Program, and GOOD, with support from the Gordon and Betty Moore Foundation and the Rita Allen Foundation.
It is available as a free, beautifully designed digital magazine for both desktop and mobile.
TABLE OF CONTENTS:
- SCIENTISTS:
Award-Winning Scientists Offer Advice to the Next President of the United States - PUBLIC OPINION:
National Survey Reveals Americans' Most Important Scientific Priorities - GOVERNMENT:
The Nation's Science and Health Agencies Face a Credibility Crisis: Can Their Reputations Be Restored? - TELEVISION:
To Make Science Engaging, We Need a Sesame Street for Adults - IMMIGRATION:
Immigrant Scientists—and America's Edge—Face a Moment of Truth This Election - RACIAL JUSTICE:
Democratize the White Coat by Honoring Black, Indigenous, and People of Color in Science - EDUCATION:
I'm a Black, Genderqueer Medical Student: Here's My Hard-Won Wisdom for Students and Educational Institutions - TECHNOLOGY:
"Deep Fake" Video Technology Is Advancing Faster Than Our Policies Can Keep Up - VOTERS:
Mind the (Vote) Gap: Can We Get More STEM Students to the Polls? - EXPERTS:
Who Qualifies as an "Expert" and How Can We Decide Who Is Trustworthy? - SOCIAL MEDIA:
Why Your Brain Falls for Misinformation—And How to Avoid It - YOUTH:
Youth Climate Activists Expand Their Focus and Collaborate to Get Out the Vote - SUPREME COURT:
Abortions Before Fetal Viability Are Legal: Might Science and a Change on the Supreme Court Undermine That? - NAVAJO NATION:
An Environmental Scientist and an Educator Highlight Navajo Efforts to Balance Tradition with Scientific Priorities - CIVIC SCIENCE:
Want to Strengthen American Democracy? The Science of Collaboration Can Help
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.