A new research study shows that human behavior, like lockdowns, influences the evolution of COVID-19, leading to strains that are more transmissible earlier in their lifecycle.
Using artificial intelligence technology and mathematical modeling, a research group led by Nagoya University has revealed that human behavior, such as lockdowns and isolation measures, affect the evolution of new strains of COVID-19. SARS-CoV-2, the virus that causes COVID-19, developed to become more transmissible earlier in its lifecycle. The researcher's findings, published today (November 21) in the scientific journal Nature Communications, provide new insights into the relationship between how people behave and disease-causing agents.
Virus Evolution and Human Impact
As with any other living organism, viruses evolve over time. Those with survival advantages become dominant in the gene pool. Many environmental factors influence this evolution, including human behavior. By isolating sick people and using lockdowns to control outbreaks, humans may alter virus evolution in complicated ways. Predicting how these changes occur is vital to develop adaptive treatments and interventions.
Viral Load and Transmission
An important concept in this interaction is viral load, which refers to the amount or concentration of a virus present per ml of a bodily fluid. In SARS-CoV-2, a higher viral load in respiratory secretions increases the risk of transmission through droplets.
Viral load relates to the potential to transmit a virus to others. For example, a virus like Ebola has an exceptionally high viral load, whereas the common cold has a low one. However, viruses must perform a careful balancing act, as increasing the maximum viral load can be advantageous, but an excessive viral load may cause individuals to become too sick to transmit the virus to others.
AI-Assisted Research Findings
The research group led by Professor Shingo Iwami at the Nagoya University Graduate School of Science identified trends using mathematical modeling with an artificial intelligence component to investigate previously published clinical data.
They found that the SARS-CoV-2 variants that were most successful at spreading had an earlier and higher peak in viral load. However, as the virus evolved from the pre-Alpha to the Delta variants, it had a shorter duration of infection.
The researchers also found that the decreased incubation period and the increased proportion of asymptomatic infections recorded as the virus mutated also affected virus evolution.
Evolution From Wuhan to Delta Strain
The results showed a clear difference. As the virus evolved from the Wuhan strain to the Delta strain, they found a 5-fold increase in the maximum viral load and a 1.5-fold increase in the number of days before the viral load peaked.
Human Behavior and Virus Evolution
Iwami and his colleagues suggest that human behavioral changes in response to the virus, designed to limit transmission, were increasing the selection pressure on the virus. This caused SARS-CoV-2 to be transmitted mainly during the asymptomatic and presymptomatic periods, which occur earlier in its infectious cycle. As a result, the viral load peak advanced to this period to spread more effectively in the earlier pre-symptomatic stages.
Public Health Strategies and Virus Evolution
When evaluating public health strategies in response to COVID-19 and any future potentially pandemic-causing pathogens, it is necessary to consider the impact of changes in human behavior on virus evolution patterns. "We expect that immune pressure from vaccinations and/or previous infections drives the evolution of SARS-CoV-2," Iwami said. "However, our study found that human behavior can also contribute to the virus's evolution in a more complicated manner, suggesting the need to reevaluate virus evolution."
Their study suggests the possibility that new strains of coronavirus evolved because of a complex interaction between clinical symptoms and human behavior. The group hopes that their research will speed up the establishment of testing regimes for adaptive treatment, effective screening, and isolation strategies.
Reference: "Isolation may select for earlier and higher peak viral load but shorter duration in SARS-CoV-2 evolution" by Junya Sunagawa, Hyeongki Park, Kwang Su Kim, Ryo Komorizono, Sooyoun Choi, Lucia Ramirez Torres, Joohyeon Woo, Yong Dam Jeong, William S. Hart, Robin N. Thompson, Kazuyuki Aihara, Shingo Iwami and Ryo Yamaguchi, 21 November 2023, Nature Communications.
DOI: 10.1038/s41467-023-43043-2
News
Scientists Uncover Hidden Blood Pattern in Long COVID
Researchers found persistent microclot and NET structures in Long COVID blood that may explain long-lasting symptoms. Researchers examining Long COVID have identified a structural connection between circulating microclots and neutrophil extracellular traps (NETs). The [...]
This Cellular Trick Helps Cancer Spread, but Could Also Stop It
Groups of normal cbiells can sense far into their surroundings, helping explain cancer cell migration. Understanding this ability could lead to new ways to limit tumor spread. The tale of the princess and the [...]
New mRNA therapy targets drug-resistant pneumonia
Bacteria that multiply on surfaces are a major headache in health care when they gain a foothold on, for example, implants or in catheters. Researchers at Chalmers University of Technology in Sweden have found [...]
Current Heart Health Guidelines Are Failing To Catch a Deadly Genetic Killer
New research reveals that standard screening misses most people with a common inherited cholesterol disorder. A Mayo Clinic study reports that current genetic screening guidelines overlook most people who have familial hypercholesterolemia, an inherited disorder that [...]
Scientists Identify the Evolutionary “Purpose” of Consciousness
Summary: Researchers at Ruhr University Bochum explore why consciousness evolved and why different species developed it in distinct ways. By comparing humans with birds, they show that complex awareness may arise through different neural architectures yet [...]
Novel mRNA therapy curbs antibiotic-resistant infections in preclinical lung models
Researchers at the Icahn School of Medicine at Mount Sinai and collaborators have reported early success with a novel mRNA-based therapy designed to combat antibiotic-resistant bacteria. The findings, published in Nature Biotechnology, show that in [...]
New skin-permeable polymer delivers insulin without needles
A breakthrough zwitterionic polymer slips through the skin’s toughest barriers, carrying insulin deep into tissue and normalizing blood sugar, offering patients a painless alternative to daily injections. A recent study published in the journal Nature examines [...]
Multifunctional Nanogels: A Breakthrough in Antibacterial Strategies
Antibiotic resistance is a growing concern - from human health to crop survival. A new study successfully uses nanogels to target and almost entirely inhibit the bacteria P. Aeruginosa. Recently published in Angewandte Chemie, the study [...]
Nanoflowers rejuvenate old and damaged human cells by replacing their mitochondria
Biomedical researchers at Texas A&M University may have discovered a way to stop or even reverse the decline of cellular energy production—a finding that could have revolutionary effects across medicine. Dr. Akhilesh K. Gaharwar [...]
The Stunning New Push to Protect the Invisible 99% of Life
Scientists worldwide have joined forces to build the first-ever roadmap for conserving Earth’s vast invisible majority—microbes. Their new IUCN Specialist Group reframes conservation by elevating microbial life to the same urgency as plants and [...]
Scientists Find a Way to Help the Brain Clear Alzheimer’s Plaques Naturally
Scientists have discovered that the brain may have a built-in way to fight Alzheimer’s. By activating a protein called Sox9, researchers were able to switch on star-shaped brain cells known as astrocytes and turn them into [...]
Vision can be rebooted in adults with amblyopia, study suggests
Temporarily anesthetizing the retina briefly reverts the activity of the visual system to that observed in early development and enables growth of responses to the amblyopic eye, new research shows. In the common vision [...]
Ultrasound-activated Nanoparticles Kill Liver Cancer and Activate Immune System
A new ultrasound-guided nanotherapy wipes out liver tumors while training the immune system to keep them from coming back. The study, published in Nano Today, introduces a biodegradable nanoparticle system that combines sonodynamic therapy and cell [...]
Magnetic nanoparticles that successfully navigate complex blood vessels may be ready for clinical trials
Every year, 12 million people worldwide suffer a stroke; many die or are permanently impaired. Currently, drugs are administered to dissolve the thrombus that blocks the blood vessel. These drugs spread throughout the entire [...]
Reviving Exhausted T Cells Sparks Powerful Cancer Tumor Elimination
Scientists have discovered how tumors secretly drain the energy from T cells—the immune system’s main cancer fighters—and how blocking that process can bring them back to life. The team found that cancer cells use [...]
Very low LDL-cholesterol correlates to fewer heart problems after stroke
Brigham and Women's Hospital's TIMI Study Group reports that in patients with prior ischemic stroke, very low achieved LDL-cholesterol correlated with fewer major adverse cardiovascular events and fewer recurrent strokes, without an apparent increase [...]
