“This shows a possible future that has not yet been fully addressed,” says Fred Adler, PhD, professor of mathematics and biological sciences at the U. “Over the next decade, the severity of COVID-19 may decrease as populations collectively develop immunity.”

The findings suggest that changes in the disease could be driven by adaptations of our immune response rather than by changes in the virus itself. Adler was senior author on the publication with Alexander Beams, first author and graduate student in the Department of Mathematics and the Division of Epidemiology at University of Utah Health, and undergraduate co-author Rebecca Bateman.

Although SARS-CoV-2 (the sometimes-deadly coronavirus causing COVID-19) is the best-known member of that virus family, other seasonal coronaviruses circulate in the human population — and they are much more benign. Some evidence indicates that one of these cold-causing relatives might have once been severe, giving rise to the “Russian flu” pandemic in the late 19th century. The parallels led the U of U scientists to wonder whether the severity of SARS-CoV-2 could similarly lessen over time.

To test the idea, they built mathematical models incorporating evidence on the body’s immune response to SARS-CoV-2 based on the following data from the current pandemic.

• There is likely a dose response between virus exposure and disease severity.
  • A person exposed to a small dose of virus will be more likely to get a mild case of COVID-19 and shed small amounts of virus.
  • By contrast, adults exposed to a large dose of virus are more likely to have severe disease and shed more virus.
  • Masking and social distancing decrease the viral dose.
• Children are unlikely to develop severe disease.
• Adults who have had COVID-19 or have been vaccinated are protected against severe disease.

Running several versions of these scenarios showed that the three mechanisms in combination set up a situation where an increasing proportion of the population will become predisposed for mild disease over the long term. The scientists felt the transformation was significant enough that it needed a new term. In this scenario, SARS-CoV-2 would become “Just Another Seasonal Coronavirus,” or JASC for short.

“In the beginning of the pandemic, no one had seen the virus before,” Adler explains. “Our immune system was not prepared.” The models show that as more adults become partially immune, whether through prior infection or vaccination, severe infections all but disappear over the next decade. Eventually, the only people who will be exposed to the virus for the first time will be children — and they’re naturally less prone to severe disease.

“The novel approach here is to recognize the competition taking place between mild and severe COVID-19 infections and ask which type will get to persist in the long run,” Beams says. “We’ve shown that mild infections will win, as long as they train our immune systems to fight against severe infections.”

The models do not account for every potential influence on disease trajectory. For example, if new virus variants overcome partial immunity, COVID-19 could take a turn for the worse. In addition, the predictions rely on the key assumptions of the model holding up.

“Our next step is comparing our model predictions with the most current disease data to assess which way the pandemic is going as it is happening,” Adler says. “Do things look like they’re heading in a bad or good direction? Is the proportion of mild cases increasing? Knowing that might affect decisions we make as a society.”

The research, published as “Will SARS-CoV-2 Become Just Another Seasonal Coronavirus?,” was supported by COVID MIND 2020 and the University of Utah.

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The consensus view of scientists is that volcanic activity at the end of the Permian period, associated with the Siberian Traps Large Igneous Province, emitted massive quantities of greenhouse gases into the atmosphere over a short time interval. This caused a spike in global temperatures and a cascade of other deleterious environmental effects.

An international team of researchers from the United States, Sweden, and Australia studied sedimentary deposits in eastern Australia, which span the extinction event and provide a record of changing conditions along a coastal margin that was located in the high latitudes of the southern hemisphere. Here, the extinction event is evident as the abrupt disappearance of Glossopteris forest-mire ecosystems that had flourished in the region for millions of years. Data collected from eight sites in New South Wales and Queensland, Australia were combined with the results of climate models to assess the nature and pace of climate change before, during, and after the extinction event.

Results show that Glossopteris forest-mire ecosystems thrived through the final stages of the Permian period, a time when the climate in the region was gradually warming and becoming increasingly seasonal. The collapse of these lush environments was abrupt, coinciding with a rapid spike in temperatures recorded throughout the region. The post-extinction climate was 10-14°C warmer, and landscapes were no longer persistently wet, but results point to overall higher but more seasonal precipitation consistent with an intensification of a monsoonal climate regime in the high southern latitudes.

Because many areas of the globe experienced abrupt aridification in the wake of the “great dying,” results suggest that high-southern latitudes may have served as important refugia for moisture-loving terrestrial groups.

The rate of present-day global warming rivals that experienced during the “great dying,” but its signature varies regionally, with some areas of the planet experiencing rapid change while other areas remain relatively unaffected. The future effects of climate change on ecosystems will likely be severe. Thus, understanding global patterns of environmental change at the end of the Paleozoic can provide important insights as we navigate rapid climate change today.

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A new study led by Dr. Corentin Bochaton and Professor Nicole Boivin of the Max Planck Institute for the Science of Human History in Jena, Germany, reveals far greater extinctions among the snakes and lizards of Guadeloupe following European colonization than previously believed. Partnering with colleagues from Centre National de la Recherche Scientifique (CNRS), Muséum National d’Histoire Naturelle (MNHN), Institut de Recherche pour le Développement (IRD) and the Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), the team studied an extraordinary 43,000 individual bone remains from fossil and archaeological assemblages on six islands, ultimately revealing that 50% to 70% of Guadeloupe’s squamate species went extinct after the arrival of European colonialists.

This enormous loss of biodiversity stands in stark contrast to the pre-colonial record, which shows that Indigenous populations co-existed with the islands’ snakes and lizards for thousands of years. In fact, the biodiversity of Guadeloupe’s snakes and lizards actually increased during the long history of Indigenous habitation, with no recorded extinctions and the introduction of two new lizard species.

“The long-term data from Guadeloupe are concerning,” notes Professor Boivin, Director of the Department of Archaeology at the MPI in Jena. “Snakes and lizards persisted through a broad range of climatic, environmental and human-induced changes on Guadeloupe over thousands of years. They do not appear to be sensitive animals. Yet in the last few hundred years, their diversity has plummeted.”

The new paper underscores the potential of archaeological and fossil records to provide information that is highly relevant in the modern world.

“Our research strongly advocates for the study of past biodiversity to address current conservation issues and for the study of less charismatic animals like reptiles, which are an essential part of tropical ecosystems,” says Bochaton.

The use of fossil data from Guadeloupe allowed the team to closely examine the dynamics of the extinctions, revealing links between species’ body size, habitat preference, and risk of extinction. Medium-sized, terrestrial species sustained the greatest losses, implicating recently introduced mammalian predators such as mongooses and cats as primary drivers in Guadeloupe’s reptile extinctions.

The extinction trends also highlight the impacts of a shift to intensive colonial agriculture. The destruction and fragmentation of habitats, combined with the degradation of soil and decimation of insect populations, placed enormous pressure on Guadeloupe’s snake and lizard species.

“In recent years, recognition of early human impacts has led to a kind of acceptance of humans as this inherently destructive species,” says Professor Boivin. “Yet the Guadeloupe data clearly show that Indigenous lifeways were supportive of snake and lizard biodiversity, whereas European ones were not. This provides us with important information for future management and sustainability initiatives, and calls into question some of the ways conservationists deal with Indigenous communities globally.”

The researchers hope that more of such studies will help managers and conservationists create realistic, data-driven strategies for mediating societal impacts on ecosystems.

“Archaeology budgets all around the world are under threat,” observes Professor Boivin. “But without our past, we move forward blindly. Study of the past, present and future must be intertwined.”