Two promising new ways to prevent cholera are on the horizon. One is an entirely new kind of vaccine. The other is as simple as a cup of yogurt.
Both may offer fast, cheap protection from explosive outbreaks of a disease that claims tens of thousands of lives each year.
The research has so far only been done in animals. Human studies are yet to come.
Cholera causes such serious diarrhea that it can kill within hours. Current vaccines take at least 10 days to work, don’t provide complete protection and don’t work well for young children.
One group of scientists working to create a better vaccine engineered cholera bacteria that are missing the genes that make the microbe toxic.
The researchers fed the modified bacteria to rabbits. The microbes colonized the animals’ guts but did not make them sick.
When the scientists then fed rabbits normal, disease-causing cholera 24 hours later, most of the animals survived.
Those that did get sick took longer to do so than rabbits given unmodified bacteria, or modified bacteria that had been killed. Those animals died within hours.
The engineered cholera bacteria provided protection much faster than a conventional vaccine. They acted as a probiotic: colonized the animals’ intestines in less than a day and prevented the disease-causing microbes from getting a foothold.
The researchers expect that the modified bacteria will also act like a typical vaccine, stimulating the body’s immune system to fight a future cholera infection.
“This is a new type of therapy,” Harvard University Medical School microbiologist Matthew Waldor said. “It’s both a probiotic and a vaccine. We don’t know the right name for it yet.”
In another study in the same journal, a group of researchers discovered that a microbe commonly found in yogurt, cheese and other fermented dairy products can prevent cholera infection.
Bioengineer Jim Collins at the Massachusetts Institute of Technology and colleagues had been working on genetically modifying the bacteria, known as Lactococcus lactis, to treat cholera.
It hadn’t been working.
But they accidentally discovered that unmodified L. lactis keeps cholera germs in check by producing acid that the disease-causing microbes can’t tolerate.
Feeding mice doses of L. lactis bacteria every 10 hours nearly doubled their survival rate from cholera infection.
“It was remarkably surprising and satisfying,” Colllins said. “We were really getting frustrated.”
They also designed a strain of L. lactis that turns a cholera-infected mouse’s stool red. It could be a useful diagnostic, for example, to identify those carrying the bacteria but not showing symptoms.
Collins said pills of L. lactis bacteria — or simply ample supplies of fermented milk products — could be “a very inexpensive, safe and easy-to-administer way to keep some of these outbreaks in check.”
Waldor said his group’s modified-cholera vaccine also could be grown and packaged in pills quickly and easily in case of an outbreak.
Both caution that these animal studies are a long way from new treatments for human patients. They need to be proven in clinical trials.
The two studies could not only have an impact on cholera, but could also influence how doctors treat other intestinal diseases and manage gut health, according to Robert Hall, who oversees research funded by the National Institute of Allergy and Infectious Diseases.
While fermented foods promising better health are widely available, “the studies with probiotics in the field have really seldom shown great effectiveness when they’re done scientifically,” Hall said.
The work Collins’s group did not only shows effectiveness, but explains how it works: by “making the intestine inhospitable” to cholera, he added.
Hall wrote a commentary accompanying the two studies.
Other gut diseases work the same way as cholera, he noted, so it’s possible that other microbes could be developed that block harmful germs from gaining a foothold while acting as vaccines at the same time.
The scientific community has long acknowledged that vaccination work and have saved millions of lives. However, a vocal community, particularly in the U.S., believes that vaccination expose children to health risks and can cause harm.
It can be easy to write off these opinions, but psychology researchers have long known of many cognitive biases that can lead people to make poor judgments. Several of these researchers are interested in how people end up receiving and believing fallacious ideas as they relate to vaccines.
The human mind isn’t like a computer. Our brains aren’t composed of truth values coded as ones and zeros. Emotion, confidence and memory can all impact how we form beliefs. The problem is we often don’t recognize when we aren’t thinking logically.
Gordon Pennycook, a researcher at Canada’s University of Regina, said he’s interested in “the tendency for people to be lazy in the way that they think.” Essentially, he said, high-level reasoning takes a lot of mental effort, and we humans are cognitive misers. If we don’t have to think that hard, we won’t.
“Part of the problem, though,” Pennycook told VOA, “is that when it comes to more complicated domains, like in the realm of science, our intuitions are often wrong. So we need to spend more time thinking about it.”
In 2015, Pennycook published a paper titled On the reception and detection of pseudo-profound bulls**t that focused on whether people find meaning in statements randomly made up of common buzzwords. One example: “Hidden meaning transforms unparalleled abstract beauty.”
He found that people who ascribed meaning to these nonsensical statements were more likely to believe in complementary and alternative medicine, which Pennycook asserts are the same people who are less likely to get vaccines.
“I don’t want to call it open-minded, but it’s a so-open-minded-that-your-brain-kind-of-falls-out type of situation,” he said.
The unwillingness or inability to think critically is somewhat tied to another well-known psychological phenomenon, the Dunning-Kruger effect. First formally identified in 1999 by its namesakes, the cognitive bias refers to a broken link between actual knowledge and perceived competence.
As Pennycook puts it, “The incompetent are too incompetent to recognize their incompetence.”
For example, people with little knowledge of vaccines may feel extra certain about the little information they have, whether it’s correct or not. Pennycook noted this can create the frustrating situation where “the people we want to help the most are the least aware of how much help they need.”
And when people feel confident, they aren’t likely to try to challenge those beliefs or ideas. This phenomenon is referred to as confirmation bias.
Panayiota Kendeou, an educational psychologist at the University of Minnesota, said the pre-existing belief that vaccines are dangerous “influences how [anti-vaccine parents] evaluate any information that they come across, and they view the information in alignment with their pre-existing beliefs.”
Confirmation bias creates a filter on new information. Information that a person agrees with is strengthened, while evidence to the contrary is ignored. In Kendeou’s opinion, “that’s the major or main bias when it comes to vaccinations.”
Misconceptions and misinformation
Kendeou studies reading comprehension and learning, but is particularly interested in what those messages contain. She is an expert in misinformation and has researched how inaccurate or totally misleading information is assessed by a person reading it.
She decided to test whether she could change the way people engage with written misinformation. Kendeou had participants read messages about vaccination, but some of the participants were told to pay special attention to who made claims and whether those claims made sense.
Kendeou found corrective measures like this did help those participants recognize misleading information. And, she told VOA, “what we find a month later is that we get some maintenance of the effect.”
It wasn’t a large difference, but participants were still better at correctly rejecting bad information about vaccines than they were before the test.
When reflecting on how to reach anti-vaccine people, Kendeou said, “Having good logical arguments, it’s a great first step. But also alerting [people] that they need to pay attention who provides those logical arguments is even more important.”
Fear as double-edged sword
Unfortunately, accepting new correct information can be difficult if a person is feeling fearful.
“What we know from our work is that negative emotions like fear and anxiety narrow your attention,” Kendeou said. “And when you end up in that state of mind, you do end up focusing on certain information and not other [information] because of that narrowness in attention.”
Fear of an immediate threat, even one that’s not real — like getting the flu from the influenza vaccine — restricts a person’s ability to see the whole situation. That metaphorical tunnel vision can limit people’s ability to think critically.
But Derek Powell, a postdoctoral scholar at Stanford University, suggests that fear could also change the minds of people who don’t support vaccines. “At root, that [fear] is kind of the thing that’s driving this, for good or ill,” he said.
Rather than focusing on the oft-disproven idea that the MMR vaccine causes autism, Powell and his colleagues wanted to test if a message about the severity and risk of contracting measles, mumps or rubella convinced parents that vaccines are necessary. In a 2015 experiment, they did just that.
Powell assigned participants to one of three groups. The “fear” group was told about the chances of catching an immunizable disease and the resulting severe symptoms. In a second group, participants heard about studies proving vaccines don’t cause autism. A third group was given no additional information.
Powell said the idea was “even if you thought there was a little bit of risk to a vaccine, if we persuaded you there was a lot of risk to not vaccinating, that might kind of overall tip the scale in favor of vaccination.”
As expected, participants who learned about the risks of contracting preventable diseases were more supportive of vaccines. Interestingly, Powell noted that “emphasizing the safety of vaccines in scientific research showing there was no autism link between MMR vaccine and autism wasn’t really effective.”
It seems that just refuting an existing belief about vaccines isn’t enough. Powell said that some beliefs can be “sticky,” in that they are difficult to dismiss.
Kendeou, the University of Minnesota educational psychologist, agrees, saying while there are ways to combat bad information on vaccines, “there is no magic ‘erase and replace’ strategy.” Misconceptions, she said, never fully go away, but we can lessen their impact by reminding people to think critically and seek good evidence to refute bad arguments.
Researchers and communicators still find it difficult to keep that advice in mind.
“There’s a tendency to want to shake somebody until they start acting sensible, and I totally understand it,” Powell said. “I’ve felt it myself, but I don’t think it’s actually going to work in terms of changing their minds.”
For at least one previously anti-vaccine mom, Powell is correct.
Carli Leon, a mother of two children and previously self-described “loud voice” against vaccinations, said insulting comments online didn’t change her mind.
“When people would ridicule me and call me a bad mother, it only made me dig my heels in more. What helped me was people asking me questions [that] got me to think. That got me to recognize the hypocrisy of the anti-vaxx community and my own hypocrisy with my own beliefs that I had,” Leon said.
“You never know who is reading these posts online,” she added. “It might just change somebody’s mind.” (VOA)