The likelihood of an extreme infectious disease epidemic — similar to the COVID-19 pandemic — could triple in the coming decades, according to a recent study published in the Proceedings of the National Academy of Sciences.
The chance of someone seeing a pandemic like COVID-19 during their lifetime is about 38%, which could double in the years to come.
The possibility of another pandemic is "going to probably increase because of all of the environmental changes that are occurring," William Pan, PhD, one of the study authors and an associate professor of global environmental health at Duke University, told ABC News.
Pan and colleagues looked at data from the past 400 years to estimate the chance of extreme epidemics each year. They looked at death rates, the length of previous epidemics, and the rate of new infectious diseases.
The rate of occurrence of epidemics varies widely across time, the researchers said, but the chance of an extreme epidemic can be calculated. Recent estimates show that infectious diseases that are passed from animals to humans — also called zoonotic diseases — are becoming more common due to climate change.
With zoonotic diseases such as COVID-19, animals are often reservoirs of contagious bacteria and viruses. That means they carry bacteria or a virus, which can mutate and evolve, and humans may become infected through direct contact or indirectly through soil, water, or surfaces.
"As you make that interface between humans and the natural world smaller, we just come in more contact with those things," Pan told ABC News. "Climate enhances the ability for viruses to infect us more easily."
Along with the COVID-19 pandemic, another example of this is the recurrence of Ebola outbreaks in West Africa in recent years, including this year.
"There’s evidence that there is loss of forests in West Africa for palm oil. There’s a whole story around the palm oil industry, destroying forest tropics to plant palm oil trees," Aaron Bernstein, MD, director of the Center for Climate, Health, and the Global Environment at the Harvard T.H. Chan School of Public Health, told ABC News.
"In this case, there are bats that live in those forests, but they can’t live in palm oil plantations," he said. "And so those bats moved to a part of West Africa where they infected people with Ebola."
Zoonotic diseases now account for 60% of all diseases and 75% of emerging diseases, according to the CDC. Although anyone can get sick from a zoonotic disease, the groups most at risk include children under age 5, adults over age 65, pregnant women, and people with weak immune systems.
As more infectious diseases emerge, scientists and public health experts are racing to develop tests, treatments, and vaccines, often after the infection numbers are already out of control, ABC News reported. But little goes toward prevention of these outbreaks in the first place.
"We can’t deal with pandemics with Band-Aids, meaning after waiting until diseases show up and then trying to figure out how to solve them," Bernstein said.
To prevent another major pandemic from disrupting society, countries need to invest in surveillance systems and share information about the early signs of potential viral infections, Pan said.
"There’s some places in the world where we don’t even have the basic capacity to evaluate or test strains, viral fevers coming into hospitals," he said. "And so, a lot of those things go unchecked until it’s too late."
Global budgets also tend to go toward treatment of disease, rather than prevention at the source.
"We need to address spillover, and that means we need to protect habitats. We need to tackle climate change," Bernstein said. "We need to address the risk of large-scale livestock production because a lot of the pathogens move from wild animals into livestock and then into people."
Sources:
Proceedings of the National Academy of Sciences: "Intensity and frequency of extreme novel epidemics."
ABC News: "Climate change may make pandemics like COVID-19 much more common."
CDC: "One Health Basics: Zoonotic Diseases."
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Cite this: Climate Change May Make Pandemics More Common - Medscape - Sep 12, 2022.
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