Banner image: Professor Mark Hernandez and doctoral graduate Marina Nieto-Caballero stand inside the 10-cubic-meters bioaerosol chamber used to study live airborne coronavirus persistence in the Environmental Engineering disinfection laboratory at the Sustainability, Energy and Environment Complex (SEEC). (Credit: Patrick Campbell / CU Boulder)
Three years ago this week, Colorado recorded its first known cases of COVID-19. A week later, on March 12, CU Boulder announced its first positive case and quickly shifted to fully remote classes.
Meanwhile, researchers at CU and universities across the country jumped into action to learn everything they could about the virus, including how to test for and trace it; how to prevent its spread; and how to develop a vaccine to reduce its death toll.
Today, the pandemic and its impacts persist. While deaths in the U.S. are down significantly from peaks in previous years, in 2023 COVID-19 still kills more than 3,500 people each week and tens of millions still struggle with serious, lasting health effects.
Yet we know more than ever before about the virus and how to stop the next pandemic before it starts. Here’s a look at what CU Boulder researchers learned in year three.
COVID-19 is still a public health threat—but we can end it
While the U.S. federal public health emergency is set to expire on May 11, it is still a global public health threat and continues to disproportionately impact vulnerable populations around the world, according to 386 multidisciplinary experts from more than 100 countries and territories.
The authors of a Nature paper published in November recommended countries take a “vaccine-plus” approach to end the pandemic, including improved indoor air ventilation and filtration, increased masking, testing and treatment. They also emphasized a need to address the global inequities involved in access to vaccinations and healthcare.
“Unfortunately, COVID-19 is not yet over,” said Jose-Luis Jimenez, co-author of the study, distinguished professor of chemistry at CU Boulder and fellow at the Cooperative Institute for Research in Environmental Sciences (CIRES). “But there are many things we can and should be doing about it here in the U.S. and across the world, and a high priority should be paying attention to and taking action by cleaning our indoor air.”
Jimenez and environmental engineering professor Shelly Miller are also co-authors on a recent publication in Clinical Infectious Diseases, which argues that the World Health Organization (WHO) dismissed scientists’ concerns at the start of the pandemic that the SARS-CoV-2 virus spreads through airborne particles (which float in the air like smoke), leading to avoidable consequences that can be learned from.
Take more care in drier air
Recent CU Boulder research has found that airborne particles carrying coronavirus can remain infectious for twice as long in drier air, in part because the saliva emitted with them serves as a protective barrier around the virus, especially at low humidity levels.
“It shows this virus can hang around for quite a while—hours, even,” said Mark Hernandez, senior author of the study and S. J. Archuleta Professor of Civil and Environmental Engineering.
This first-of-its kind study published in PNAS Nexus carries implications for mitigating transmission of coronavirus, as well as other viruses, in drier climates across the country, as well as in airplane cabins and during dry winter months worldwide.
Humidifying indoor spaces is expensive and inefficient, however, said Hernandez. Instead, adding high efficiency particulate air (HEPA) air filters, opening windows and improving ventilation are all easy and affordable measures anyone can implement.
Given a moment to think, people choose to lower risks
When people simply take a moment to reflect on the consequences of their behavior, they tend to choose options that impose fewer risks on other people, according to research from Leaf Van Boven, professor of psychology and neuroscience.
The international study of 13,000 people, published in November in PNAS Nexus, was conducted at the height of the pandemic. Van Boven and his colleagues presented the global participants with hypothetical scenarios related to joining social gatherings during the pandemic, for which they had to decide to attend, cancel, or reduce capacity.
But before they did so, some participants were instructed to pause and practice a technique called “structured reflection.” Those in the structured reflection group were significantly more likely to err on the side of minimizing public health risks.
As COVID-19 restrictions lift, such personal responsibility will grow increasingly important.
“I would encourage everyone to develop a habit of asking themselves when they are considering any sort of large social gathering: What is the risk you might impose on other people, and is the benefit of the gathering worth the risk?” said Van Boven.
Students stepped up at CU and across the country
A study in BMC Public Health from researchers at CU Boulder, Colorado State University (CSU) and the Centers for Disease Control and Prevention (CDC) found that more than 90% of people on CU Boulder and CSU campuses wore masks correctly amid the pandemic during spring 2021. The new research indicates that students understood masks’ effectiveness, knew masking helped them take more classes in person and generally care about the health of others.
“The study supports the idea that masks are an effective, low-cost measure to reduce disease transmission and establishes masking as a viable way to reduce respiratory disease transmission on college campuses,” says Tanya Alderete, assistant professor in the Department of Integrative Physiology at CU Boulder and a principal investigator of the project.
Germicidal ultraviolet light remains a useful tool
A study led by scientists at the Cooperative Institute for Research in Environmental Sciences (CIRES) and CU Boulder has helped shine a light on another approach to disinfecting our shared indoor air: germicidal ultraviolet light (GUV), which can inactivate airborne pathogens but also has potential to create an unhealthy indoor “smog.”
Published in Environmental Science & Technology Letters, the work found that after GUV disinfection, the amount of harmful secondary chemicals in indoor air have an impact, but are not so detrimental as to recommend against the use of GUV. This suggests that GUV can be used to fight COVID, as well as influenza and respiratory syncytial virus (RSV), in environments at high risk of virus transmission, such as emergency waiting rooms, restaurants and gyms.
Working to prevent the next pandemic
CU Boulder virologist Sara Sawyer’s career was inspired by the defining pandemic of her childhood: the HIV/AIDS pandemic. Throughout the ongoing coronavirus pandemic, she has spent her time trying to prevent the next one.
Sawyer has spent the last 15 years gathering hundreds of samples from primate, rodent, bat and other mammalian species to better understand what evolution has taught them about how to live with viruses. In her lab at CU Boulder’s BioFrontiers Institute, she also employs cutting-edge genetic sequencing and lab techniques to better understand why when some viruses jump into new species, some succeed, and others fizzle out.
Her lab’s research has found that genetics plays a role, not only in how viruses spread within the same species, but also how they jump from species to species, including to people.
In September, she and her colleagues identified an obscure family of viruses, already endemic in wild African primates and known to cause Ebola-like symptoms in some monkeys, that is, as they put it, “poised for spillover” to humans. While no human infections have been reported to date, she urges the scientific community to be vigilant.
“COVID is just the latest in a long string of spillover events from animals to humans, some of which have erupted into global catastrophes,” Sawyer said. “Our hope is that by raising awareness of the viruses that we should be looking out for, we can get ahead of this, so that if human infections begin to occur, we’re on it quickly.”
Diet and lifestyle factors might reduce disease risks
Besides avoiding infection and reducing transmission, what can people do?
Feeding our gut microbes with healthy foods, spices and antioxidants, as well as addressing our stress and balancing physical activity with adequate recovery are some actions we can take to give ourselves a chance at less severe outcomes and full recovery following infection, said Barbara Demmig-Adams, professor of distinction and director of the EBIO Honors Program within the Department of Ecology and Evolutionary Biology.
Demmig-Adams is co-author on a study published last year in the American Journal of Lifestyle Medicine, detailing how the human body is predisposed to chronic, low-level inflammation—which puts us at a biological disadvantage when fighting off the virus that causes COVID-19.
Due to our bodies’ inflammatory responses, she notes that we should be just as careful about overexerting our bodies as not moving them enough. If you are actively sick or recently recovered, it may be wise to schedule in more rest and recovery time than anticipated.