Health

New single-dose, temperature-stable rabies vaccines could expand global access

Amber Elise Carlson — Thu, 04 Sep 2025 19:46:39 +0000

New single-dose, temperature-stable rabies vaccines could expand global access Amber Elise Carlson Thu, 09/04/2025 - 13:46

Amber Carlson

A pair of gloved hands holds a syringe and a vial with a vaccine solution. (Credit: Adobe Stock)

Roughly 60,000 people worldwide die every year from rabies, a dreaded virus that attacks the nervous system and can trigger aggression, seizures, paralysis and coma.

In industrialized countries, infections and deaths in humans are rare, thanks to vaccines widely given to pets and people for prevention and available as a life-saving treatment once someone has been exposed. But in developing countries, including rural parts of Asia and Africa, rabies remains a major threat.

Now, 91ɫ�� researchers have discovered a new way to make human rabies vaccines that could greatly expand access to immunization across the globe. The new method, outlined in an August 2025 paper in the Journal of Pharmaceutical Sciences, creates shots that are temperature-stable—meaning they don’t need to be stored at cold temperatures like traditional rabies vaccines.

These innovative shots also combine multiple timed-release doses into a single injection, potentially reducing the number of health care visits each person needs and helping to break down barriers to care. The same process could also be used to create other vaccines, including those for human papillomavirus (HPV) and human immunodeficiency virus (HIV).

“We think the implications of this are huge,” said Ted Randolph, a professor in 91ɫ��’s Department of Chemical and Biological Engineering and the lead author of the new study. “We’re really excited about it.”

Challenges of current rabies vaccines

Vaccines can work in a variety of ways. Some, like vaccines against flu or rabies, expose the body to weakened, inactivated or killed viruses. This teaches the body to recognize proteins found on their surfaces and create antibodies that fight future infections by binding to those proteins. Others, like protein-based vaccines for Covid, contain select proteins from the target pathogen that can trigger a similar immune response.

From left, Ted Randolph and colleague Robert Garcea pose for a photo. (Credit: Glenn Asakawa)

All currently marketed vaccines need to be kept refrigerated or frozen—sometimes at temperatures as low as minus 76 degrees Fahrenheit—because the proteins in them start to degrade at warmer temperatures.

Like milk that sat out on the counter too long, a vaccine solution can curdle as its proteins break down and clump together. At that point, the shots are no longer effective. Cooling them slows down the protein degradation process, said Randolph.

“The proteins basically want to make cheese,” he said. “You have to keep them from making cheese for long enough that you can manufacture the vaccines, get them to pharmacies and hospitals, and get them to patients.”

This makes it difficult, if not impossible, to administer traditional rabies vaccines in regions that lack electricity or don’t have the specialized cold storage equipment needed. In areas with electricity but poor infrastructure, a single power outage can wipe out vaccine supplies for entire communities.

The rabies vaccine also requires between three and five doses at timed intervals, depending on the patient. People in developing countries tend to visit doctors less often and have a harder time accessing medical care, so they are less likely to get all the needed doses.

‘Sapphire-coated Jolly Ranchers’

Even at warm temperatures, the shots developed by Randolph’s team don’t degrade.

To make them, the team sprays sugar solutions containing inactivated rabies viruses and other vaccine components through nozzles that make a fine mist, which dries to form a powder of microparticles. These microparticles have a glassy texture similar to that of a hard candy. The rabies virus proteins are immobilized and preserved in the candy coating, like ancient insect fossils trapped in amber.

Next, the team coats the candied particles with a layer of aluminum oxide (sapphire) of precisely controlled nanoscopic thickness using a process called atomic layer deposition pioneered by Alan Weimer and Steven George, professors in engineering and chemistry at 91ɫ��.

Because sapphire dissolves very slowly once injected into a patient, the nanoscopic sapphire layer protects the sugar-coated vaccine particles for days to weeks, depending on the thickness of the sapphire layer applied on the microparticles. When the sapphire starts to break down, the sugar layer dissolves, and the vaccine particles are released into the body one dose at a time.

A microscopic image shows vaccine particles with a sapphire coating. These particles are fractured to show the coating. (Credit: Ted Randolph)

“We're basically making sapphire-coated Jolly Ranchers,” Randolph said.

These vaccines are stable at high temperatures, can be stored in a dry powder form and delivered in bulk to parts of the world that lack cold-storage capacity.

“You can now take these vaccines to places without refrigeration, and even to places that get hot,” Randolph said. “So transportation through rural India or wherever you're going is no longer a problem.”

It’s too soon to know how effective these vaccines are in humans. Currently, they’re being tested in animals, and human clinical trials are at least a couple of years away. But the results from early testing have been promising.

In mice, the researchers found that even single injections of the spray-dried, sapphire-coated vaccine powders sparked stronger immune responses than multiple doses of traditional liquid rabies vaccines. The immune responses did not weaken after storing the vaccines for three months at temperatures up to 104 degrees Fahrenheit.

Randolph and his colleague Robert Garcea, professor emeritus in 91ɫ��’s Department of Molecular, Cellular and Developmental Biology, have formed a startup company called VitriVax to bring the technology—decades in the making—to market.

“It's been 25 years of lots of talented grad students adding little bits and pieces to the puzzle. It’s the kind of thing that does require long-term dedication, work and funding,” Randolph said.

Beyond the story

Our bioscience impact by the numbers:

Top 7% university for National Science Foundation research funding
No. 30 global university system granted U.S. patents
89-plus biotech startups with roots at 91ɫ�� in past 20 years

Follow 91ɫ�� on LinkedIn

91ɫ�� engineers have developed a new method for making vaccines that combines multiple, timed-release doses into a single injection that doesn't require refrigeration.

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Video games don't rot your brain—they train it

Megan Maneval — Fri, 22 Aug 2025 13:17:32 +0000

Video games don't rot your brain—they train it Megan Maneval Fri, 08/22/2025 - 07:17

Colorado Arts and Sciences Magazine

91ɫ�� scientists have found that playing video games comes with small but significant cognitive benefits.

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DNA from extinct hominin may have helped ancient peoples survive in the Americas

Daniel William Strain — Thu, 21 Aug 2025 22:17:04 +0000

DNA from extinct hominin may have helped ancient peoples survive in the Americas Daniel William… Thu, 08/21/2025 - 16:17

Daniel Strain

Thousands of years ago, ancient humans undertook a treacherous journey, crossing hundreds of miles of ice over the Bering Strait to the unknown world of the Americas.

Now, a new study led by the 91ɫ�� suggests that these nomads carried something surprising with them—a chunk of DNA inherited from a now-extinct species of hominin, which may have helped humans adapt to the challenges of their new home.

The researchers published their results Aug. 21 in the journal "Science."

In June 2025, researchers reported that the "Harbin cranium," originally unearthed in the 1930s, likely belonged to a Denisovan. To date, it is the only known Denisovan skull. (Credit: Fu et al., Cell, 2025)

Scientists discovered remains belonging to the first known Denisovan, who likely died more than 50,000 years ago, in a cave in Russia called Denisova, hence the name. (Credit: CC photo via Wikimedia Commons)

“In terms of evolution, this is an incredible leap,” said Fernando Villanea, one of two lead authors of the study and an assistant professor in the Department of Anthropology at 91ɫ��. “It shows an amount of adaptation and resilience within a population that is simply amazing.”

The research takes a new look at a species known as Denisovans. These ancient relatives of humans lived from what is today Russia south to Oceania and west to the Tibetan Plateau. The Denisovans likely went extinct tens of thousands of years ago. Their existence, however, remains poorly understood: Scientists identified the first known Denisovan just 15 years ago from the DNA in a fragment of bone found in a cave in Russia. Like Neanderthals, Denisovans may have had prominent brows and no chins.

“We know more about their genomes and how their body chemistry behaves than we do about what they looked like,” Villanea said.

A growing body of research has shown that Denisovans interbred with both Neanderthals and humans, profoundly shaping the biology of people living today.

To explore those connections, Villanea and his colleagues including co-lead author David Peede from Brown University, examined the genomes of humans from across the globe. In particular, the team set its sights on a gene called MUC19, which plays an important role in the immune system.

The group discovered that humans with Indigenous American ancestry are more likely than other populations to carry a variant of this gene that came from Denisovans. In other words, this ancient genetic heritage may have helped humans survive in the completely new ecosystems of North and South America.

A little-known gene

Villanea added that MUC19’s function in the human body is about as mysterious as Denisovans themselves. It’s one of 22 genes in mammals that produce mucins. These proteins make mucus, which, among other functions, can protect tissues from pathogens.

“It seems like MUC19 has a lot of functional consequences for health, but we’re only starting to understand these genes,” he said.

Previous research has shown that Denisovans carried their own variant of the MUC19 gene, with a unique series of mutations, which they passed onto some humans. That kind of admixture was common in the ancient world: Most humans alive today carry some Neanderthal DNA, whereas Denisovan DNA makes up as much as 5% of the genomes of people from some populations in Oceania.

In the current study, Villanea and colleagues wanted to learn more about how these genetic time capsules shape our evolution.

The group pored through already published data on the genomes of modern humans from Mexico, Peru, Puerto Rico and Colombia where Indigenous American ancestry and DNA is common.

They discovered that one in three modern people of Mexican ancestry carry a copy of the Denisovan variant of MUC19—and particularly in portions of their genome that come from Indigenous American heritage. That’s in contrast to people of Central European ancestry, only 1% of whom carry this variant.

The researchers discovered something even more surprising: In humans, the Denisovan gene variant seems to be surrounded by DNA from Neanderthals.

“This DNA is like an Oreo, with a Denisovan center and Neanderthal cookies,” Villanea said.

Map of a land bridge connecting modern-day Russia to Alaska roughly 21,000 years ago. (Credit: U.S. National Park Service)

A new world

Here’s what Villanea and his colleagues suspect happened: Before humans crossed the Bering Strait, Denisovans interbred with Neanderthals, passing the Denisovan MUC19 to their offspring. Then, in a game of genetic telephone, Neanderthals bred with humans, sharing some Denisovan DNA. It’s the first time scientists have identified of DNA jumping from Denisovans to Neanderthals and then humans.

Later, humans migrated to the Americas where natural selection favored the spread of this borrowed MUC19.

Why the Denisovan variant became so common in North and South America but not in other parts of the world isn’t yet clear. Villanea noted that the first people who lived in the Americas likely encountered conditions unlike anything else in human history, including new kinds of food and diseases. Denisovan DNA may have given them additional tools to contend with challenges like these.

“All of a sudden, people had to find new ways to hunt, new ways to farm, and they developed really cool technology in response to those challenges,” he said. “But, over 20,000 years, their bodies were also adapting at a biological level.”

To build that picture, the anthropologist is planning to study how different MUC19 gene variants affect the health of humans living today. For now, Villanea said the study is a testament to the power of human evolution.

“What Indigenous American populations did was really incredible,” Villanea said. “They went from a common ancestor living around the Bering Strait to adapting biologically and culturally to this new continent that has every single type of biome in the world.”

Other co-authors of the new study include researchers at Brown University; the University of Washington School of Medicine; Universidad Nacional Autónoma de México; University of Copenhagen; Clemson University; University of Padova; University of Turin; University of California, Berkeley; Université Paris- Saclay; and Trinity College Dublin.

Beyond the story

Our bioscience impact by the numbers:

Top 7% university for National Science Foundation research funding
No. 30 global university system granted U.S. patents
89-plus biotech startups with roots at 91ɫ�� in past 20 years

Follow 91ɫ�� on LinkedIn

Scientists know little about Denisovans, a now-extinct relative of humans. But a gene inherited from these hominins may have helped ancient peoples adapt to the new environments of North and South America thousands of years ago.

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Why do some people age faster than others? Study IDs genes at play

Lisa Marshall — Tue, 19 Aug 2025 02:45:35 +0000

Why do some people age faster than others? Study IDs genes at play Lisa Marshall Mon, 08/18/2025 - 20:45

Lisa Marshall

As a nurse working in an elder care facility, Isabelle Foote saw it every day: Some people age better than others.

Some eased into their 90s with mind and body intact, while others battled diabetes, Alzheimer’s or mobility issues decades earlier. Some could withstand a bad fall or bout of the flu with ease, while others never left the hospital again.

“Why was this happening to them and not the person next to them who was the same age and got to go home? We really didn’t have a lot of answers,” said Foote, who left that job to become a geneticist.

In a paper published this month in the journal Nature Genetics, Foote, now a postdoctoral associate at 91ɫ��’s Institute for Behavioral Genetics, provides some clues.

Isabelle Foote left her job as an elder care nurse to use genetics to better understand aging.

She and an international team of co-authors have identified more than 400 genes associated with accelerated aging across seven different sub-types. The study reveals that different groups of genes underlie different kinds of disordered aging, a.k.a. frailty, ranging from cognitive decline to mobility issues to social isolation.

The findings lend support to what is known as the “geroscience hypothesis” — the idea that to treat the multiple chronic illnesses that come with aging, we must treat aging itself.

“To be able to identify treatments to stop or reverse accelerated biological aging, you need to know what the underlying biology is,” said Foote, first author on the paper. “This is the largest study yet to use genetics to try to do that.”

Redefining 'frailty'

The study centers around “frailty,” a catch-all term for the “multisystem physiological decline” that often comes with aging.

More than 40% of U.S. adults over age 65 are considered frail.

Doctors typically assess frailty using a 30- point index that measures everything from walking speed and grip strength to number of diagnosed illnesses and amount of social activity. The problem with this approach, said Foote, is that two people can get the same high frailty score even though one is cognitively sharp but can’t walk and another is in good physical health but has a poor memory.

This lack of distinction has made it hard for doctors to make recommendations for aging adults and for scientists to pinpoint the underlying causes of unhealthy aging.

“Aging is not just one thing. There are many ways to be frail,” said Dr. Kenneth Rockwood, a leading expert in frailty, based at Dalhousie University in Nova Scotia, Canada and co-author on the study. “The question then becomes: What genes are involved?”

To find out, the team conducted a “genome-wide association study” analyzing DNA and health information from hundreds of thousands of participants in the UK Biobank and other public datasets to see which genes were associated with 30 frailty symptoms.

They identified 408 genes associated with accelerated aging/frailty, a significant increase from the 37 genes previously identified.

Some genes, they found, were strongly linked to certain subtypes of unhealthy aging, including: “disability”; “poor cognition”; “metabolic problems” (like diabetes and heart disease); “multiple diseases”; “generally unhealthy lifestyle”; and “limited social support”.

For instance, the SP1 gene, associated with immune function and Alzheimer’s disease was strongly associated with the broad “poor cognition” subtype, whereas the FTO gene, a gene known to be associated with obesity, seemed to underly several different subtypes.

“What this paper does is not only identify sub-facets of disordered aging but also demonstrate that there is very different biology underlying them,” said senior author Andrew Grotzinger, assistant professor of psychology and neuroscience at 91ɫ��. “The tangible next step is to figure out how to treat this underlying biology.”

An anti-aging pill?

In the near term, the authors suggest that clinical measurements of frailty—which often shows up long before specific diseases—be expanded to include the six subtypes.

That way, someone diagnosed as cognitively frail could be guided toward therapies to prevent dementia, while someone frail in the metabolic domain might take steps to prevent diabetes or heart disease.

Foote envisions a day when people could get a “polygenic risk score” offering more detailed insight into what kind of unhealthy aging they are prone to.

But the holy grail, she says, would be to identify the molecular pathways that drive aging itself and develop therapies to put the brakes on.

Is a single anti-aging pill on the horizon?

Not likely, the authors say.

But could there one day be a pill to treat a package of age-related metabolic issues, and another to address numerous cognitive issues?

It’s a tantalizing idea, said Grotzinger, and genetic research could pave the way.

“This paper suggests that it’s probably not going to be a single magic pill to address all the diseases that come with aging, but maybe it doesn’t need to be hundreds anymore.”

Researchers have identified more than 400 genes associated with accelerated aging, a.k.a. frailty, across seven categories. The findings pave the way toward personalized therapies to curb disease by decelerating aging.

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Researchers have identified hundreds of genes associated with accelerated aging in hopes of someday developing therapies to slow it down. Credit: Adobe Stock

New bio-imaging device holds potential for eye and heart condition detection

Megan Maneval — Fri, 15 Aug 2025 17:50:25 +0000

New bio-imaging device holds potential for eye and heart condition detection Megan Maneval Fri, 08/15/2025 - 11:50

College of Engineering and Applied Science

Researchers at 91ɫ�� have developed a new bio-imaging device that can operate with significantly lower power and in an entirely non-mechanical way. It could one day improve detecting eye and even heart conditions.

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Raised with pets? Your immune system remembers

Megan Maneval — Fri, 15 Aug 2025 12:13:49 +0000

Raised with pets? Your immune system remembers Megan Maneval Fri, 08/15/2025 - 06:13

Colorado Arts and Sciences Magazine

91ɫ�� researchers, with an international team of colleagues, find that childhood pets are linked to healthier stress responses.

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Youth violence prevention program shown to reduce arrests by up to 75%

Lisa Marshall — Tue, 12 Aug 2025 16:10:25 +0000

Youth violence prevention program shown to reduce arrests by up to 75% Lisa Marshall Tue, 08/12/2025 - 10:10

Lisa Marshall

A 91ɫ��-led initiative to reduce youth violence in hard-hit Denver neighborhoods was associated with a 75% decline in arrests for murder, assault, robbery and other youth crimes in recent years, new research shows.

“We now have concrete data to show that when communities come together and mobilize, we can prevent youth violence, even in urban settings with a very high burden,” said senior author Beverly Kingston, director of CU’s Center for the Study and Prevention of Violence (CSPV).

The study, published in the American Journal of Criminal Justice, assesses the efficacy of the Youth Violence Prevention Center - Denver (YVPC-Denver), one of five university-community partnerships established by the Centers for Disease Control after the 1999 Columbine High School shooting.

Documentary filmmaker Antoinette "Ajay" June films Game Changer Janaya Frilot in Denver.

The centers have remained one of the only long-term federally funded efforts to address what the agency has termed the “serious public health issue” of youth violence.

Homicide is the third leading cause of death for youth ages 10 to 24 and the leading cause of death among Black youth, according to the CDC.

Now, proposed cuts to the CDC budget threaten to shutter the Denver center, housed at the CSPV, as early as next month.

“Thanks to this funding, we have been able to bring violence down in Denver while a lot of communities around the country have not,” said Dave Bechhoefer, project director for the YVPC-Denver. “To have it go away just when it is starting to get traction could have a huge impact.”

A ‘violence prevention infrastructure’

In 2011, YVPC-Denver began working with community organizations in Montbello and Park Hill to get at the root cause of youth violence plaguing the neighborhoods and come up with and implement solutions. They used a framework called Communities That Care, which hinges on two things: science-backed interventions and community involvement.

“It’s all about building a violence prevention infrastructure,” said Kingston. “Just like we have roads and bridges that we put money toward, we need to build an infrastructure that supports violence prevention throughout the life-course.”

Partner coordinator Troy Grimes, left, helps Game Changer Quavon Mosley with his new, donated tuxedo before a documentary screening.

In partnership with elementary schools, after-school programs, and faith and sports organizations, the program provided more than 3,000 youth ages 6 to 18 with training on how to handle anger and peacefully resolve conflict.

The initiative also worked with pediatricians to develop screenings for kids and get them help if they seemed at high risk of committing violence and provided mini grants to local groups matching positive adult role models with teens.

Perhaps the most visible outgrowth of the program has been the Power of One campaign, a sweeping youth-led effort in which dozens of youth, known as the Game Changers, use social media, podcasts, neighborhood block parties and more to send a message that violence is not normal.

One group of Game Changers, known as VIBEE (Violence Intervention Building Education and Empowerment) produced a film “Breaking the Cycle: Stories of Strength and Survival of Gun Violence,” which will screen in Denver this week and at 91ɫ�� this fall.

Others recently rolled out an app that connects youth with peers for help handling food insecurity, mental health issues or gang violence.

“Sometimes the people who are causing the violence are just youth having trouble at home and having a hard time getting the help they need,” said Game Changer Annecya Lawson, who joined the program after a friend was fatally shot her sophomore year in high school. “When these kids see somebody their age, who looks like them, doing stuff for the community, it can have a big impact. They’re more likely to think before they act.”

Crunching the numbers

For the study, 91ɫ�� researchers analyzed arrest data from the Denver Police Department for the five years prior (2012–16) and five years after (2017–21) Communities that Care was implemented in Park Hill.

They found that arrests fell 75%—from 1,086 per 100,000 people in 2016 to 276 per 100,000 in 2021.

The Game Changers stand with community members at the Expressions of Hope Art Therapy event in Denver in April.

The authors acknowledge that other pandemic-related factors, gentrification or violence prevention efforts could have contributed some to the declines. But rigorous statistical analysis suggests that program is "the most plausible explanation for the sharp decrease."

On average, across 74 Denver neighborhoods, youth arrests fell 18% between 2016 and 2021.

Montbello, which had implemented Communities that Care several years before Park Hill, had already established lower violence rates and maintained them throughout the study period even as they climbed sharply elsewhere amid the COVID-19 pandemic.

This suggests the violence prevention infrastructure had lasting impacts.

“In the 15 years we have been working in these communities we have seen many times, anecdotally, what can happen when communities come together to prevent violence. But to be able to have the data behind it now is incredibly exciting,” said Kingston.

Kingston recently got word that the final year of funding for the center's current five-year grant cycle is at significant risk of being revoked. Loss of the $1.2 million would jeopardize the existence of the Game Changers and make it impossible for the YVPC – Denver to continue.

“Losing this funding would be devastating,” said Kingston. “Not just for Denver but for communities nationwide looking to replicate this success.”

A 91ɫ��-led effort to help high-risk communities build a “violence prevention infrastructure” contributed to sharp declines in arrests for murder, assault and other youth crimes in Denver, new research shows. The program is now poised to lose its federal funding.

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The Game Changers, a group of young people working to curb youth violence in Denver, pose for a photo. Credit: Miss Money Shot Productions

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The Game Changers, a group of young people working to curb youth violence in Denver, pose for a photo. Credits: Miss Money Shot Productions

Study: Using cannabis and psilocybin together may increase dependence

Megan Maneval — Mon, 11 Aug 2025 19:00:07 +0000

Study: Using cannabis and psilocybin together may increase dependence Megan Maneval Mon, 08/11/2025 - 13:00

Colorado Arts and Sciences Magazine

91ɫ�� researchers studied cannabis-psilocybin users and cannabis-only users to look for similarities and differences between the two groups, including drug use motivations.

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Medical issues and neighborhood opportunity can affect infant development

Megan Maneval — Thu, 07 Aug 2025 14:57:23 +0000

Medical issues and neighborhood opportunity can affect infant development Megan Maneval Thu, 08/07/2025 - 08:57

Colorado Arts and Sciences Magazine

91ɫ�� researcher Emily Yeo finds that some babies may benefit from more support and resources so they can grow up to lead long, happy and healthy lives.

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Black Death offers clues into how childhood malnutrition shapes adult health

Daniel William Strain — Wed, 30 Jul 2025 17:33:52 +0000

Black Death offers clues into how childhood malnutrition shapes adult health Daniel William… Wed, 07/30/2025 - 11:33

Daniel Strain

The Black Death arrived on the shores of England in May 1348 and, in less than two years, spread throughout the country, killing an estimated 2 million people. The death toll from the disease, which was caused by the bacterium Yersinia pestis, got so high that officials in London and other cities opened new cemeteries where hundreds of bodies were interred every day.

According to a new study, those who died around the time of the Black Death may help scientists answer a decidedly modern question: How can malnutrition early in life shape the health of humans far into adulthood?

Illustration in the medieval manuscript Tractatus quartus bu Gilles li Muisit depicting people burying victims of the Black Death. (Credit: Public domain image via Wikimedia Commons)

The answer may be more complicated than scientists once suspected, said Sharon DeWitte, lead author of the study and a professor in the Institute of Behavioral Science and Department of Anthropology at the 91ɫ��.

In the new research, DeWitte and her colleagues examined chemical clues hidden in the teeth of nearly 275 people buried in English cemeteries before, during and after the Black Death. The team discovered something surprising: People who experienced malnutrition early in their lives may have survived threats to their health, like plague, at greater rates than their peers up until young adulthood, or roughly before the age of 30.

Those survival advantages, however, could have dropped significantly when the same individuals entered their middle and late adult years.

“What this might indicate is that if people experienced a period of starvation early in their childhoods or adolescence but survived, that could have shaped their development in ways that were beneficial in the short term but led to poor outcomes once they got older,” DeWitte said.

She and her colleagues published their findings July 30 in the journal Science Advances.

The research is part of DeWitte’s ongoing effort to understand the past to help humans living today.

“Mortality varied during a catastrophe 700 years ago in ways that might have been preventable,” she said. “My hope is that we can absorb that lesson and think about how human health can vary across different social categories today, and figure out the points of intervention where we can do something to reduce that burden.”

Childhood health

How experiences early in life shape our health long into the future is far from clear cut.

Some studies of modern humans, for example, have linked low birth weights in infants to health problems later in life. Babies born small, a possible sign of nutritional stress, seem to be more prone to illnesses like cardiovascular disease and diabetes in adulthood than the population at large.

The remnants of Thornton Abbey in Lincolnshire, United Kingdom, the site of a cemetery where victims of the Black Death were buried en masse. (Credit: CC photo by David Wright via Wikimedia Commons)

Sharon DeWitte

The Black Death, sometimes known as the second pandemic of plague, might be an ideal laboratory for studying these questions, DeWitte noted. In part, that’s because the death toll around Europe varied drastically—in some parts of England, for example, about 30% of the population died, while mortality rates reached 75% in Florence, Italy.

“It raises questions about why mortality was higher in some populations than others,” she said.

To pursue those questions, DeWitte and her colleagues turned to teeth.

Environment matters

She explained that what humans eat as infants and children leaves a mark in the development of our adult teeth—subtly shifting the types, or “isotopes,” of carbon and nitrogen atoms present in the dentine. In particular, when people experience extreme nutritional stress, their bodies will begin to break down their own fat stores and muscle, which have a different signature of isotopes than food that is eaten.

In the current study, DeWitte’s team examined the isotopes present in the teeth of hundreds of people buried in English cemeteries between 1100 to 1540 AD. They included the East Smithfield Black Death Cemetery, which opened in London in 1348 and where the bodies of hundreds of plague victims were stacked in a mass burial trenches.

DeWitte emphasizes that the team’s results are far from definitive—in many cases, the researchers don’t have any records about the humans they studied, so it’s hard to know for sure how they died or how healthy they were in life.

But the findings carry hints that malnutrition early in life may shape the health of adults in ways that aren’t necessarily good or bad—it all depends on context.

When infants or children don’t have enough to eat, DeWitte said, their bodies may develop in ways that prime them for hardship later in life. They may have altered metabolism, for example, so that they use calories, which may be scarce, more efficiently.

Those changes can be beneficial—that is, until the environment changes and food becomes more plentiful. Some evidence, for example, suggests that in the wake of the Black Death, conditions for survivors in England improved as laborers demanded higher wages.

“People who experienced nutritional stress as children may have had a mismatch with their environments later in life,” DeWitte said. “If there’s now a resource abundance, but their bodies were shaped for an environment of scarcity, they may have poor health outcomes, like packing too many fat stores, which can lead to cardiovascular disease.”

For DeWitte, the study is another example of what humans living today can learn from people who died hundreds of years ago:

“For a very long time, I've been interested in this question of why some people experience good health and others living in the exact same society don’t.”

Co-authors of the new research include Julia Beaumont and Jacqueline Towers at the University of Bradford in the United Kingdom; Brittany Walter of the Defense POW/MIA Accounting Agency; and Emily Brennan at the University of South Carolina.

Experiencing malnutrition in childhood or adolescence may not necessarily harm the health of humans into adulthood—although the relationship is complicated, a new study finds.

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Yersinia pestis bacteria seen through fluorescent imagine. (Credit: CDC)

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The Black Death was caused by Yersinia pestis bacteria, seen here through fluorescent imaging, and largely spread through fleas. (Credit: CDC)

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New single-dose, temperature-stable rabies vaccines could expand global access

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