While the new coronavirus pandemic suddenly took the world by storm, the truth is public health experts for years have warned that a virus similar to the new coronavirus would cause the next pandemic—and they say deadly infectious disease outbreaks could become more common.

The 'recurring themes' of disease outbreaks

Experts for years have warned a respiratory-borne RNA virus could cause the next global pandemic

Infectious disease experts are always on the lookout for the next pandemic, and in a report published two years ago, researchers from the Johns Hopkins Bloomberg School of Public Health predicted that the pathogen most likely to cause the next pandemic would be a virus similar to the common cold.

Specifically, the researchers predicted that the pathogen at fault for the next pandemic would be:

• A microbe for which people have not yet developed immunities, meaning that a large portion of the human population would be susceptible to infection;
• Contagious during the so-called "incubation period"—the time when people are infected with a pathogen but are not yet showing symptoms of the infection or are showing only mild symptoms; and
• Resistant to any known prevention or treatment methods.

The researchers also concluded that such a pathogen would have a "low but significant" fatality rate, meaning the pathogen wouldn't kill human hosts fast enough to inhibit its spread. As Amesh Adalja—a senior scholar at the Johns Hopkins Center for Health Security, who led the report—told Live Science's Rachael Rettner at the time, "It just has to make a lot of people sick" to disrupt society.

The researchers said RNA viruses—which include the common cold, influenza, and severe acute respiratory syndrome (or SARS, which is caused by a type of coronavirus)—fit that bill. And even though we had a good bit of experience dealing with common RNA viruses like the flu, Adalja at the time told Rettner that there were "a whole host of viral families that get very little attention when it comes to pandemic preparedness."

Not even two years later, the new coronavirus, which causes Covid-19, emerged and quickly spread throughout the world, reaching pandemic status in just a few months. To date, officials have reported more than 4.4 million cases of Covid-19 and 302,160 deaths tied to the new coronavirus globally. In the United States, the number of reported Covid-19 cases has reached more than 1.4 million and the number of reported deaths tied to the new coronavirus has risen to nearly 86,000 in just over three months.

Although public health experts had warned about the likelihood of a respiratory-borne RNA virus causing the next global pandemic, many say the world was largely unprepared to handle this type of infectious disease outbreak. And as concerning as that revelation may be on its own, perhaps even more worrisome is that public health experts predict life-threatening infectious disease outbreaks are likely to become more common—meaning we could be susceptible to another pandemic in the future.

Why experts think deadly infectious disease outbreaks could become more common

As the Los Angeles Times's Joshua Emerson Smith notes, infectious disease experts for more than ten years now have noted that "[o]utbreaks of dangerous new diseases with the potential to become pandemics have been on the rise—from HIV to swine flu to SARS to Ebola." For instance, a report published in Nature in 2008 found that the number of emerging infectious disease events that occurred in the 1990s was more than three times higher than it was in the 1940s.

Many experts believe the recent increase in infectious disease outbreaks is tied to human behaviors that disrupt the environment, "such as deforestation and poaching," which have led "to increased contact between highly mobile, urbanized human populations and wild animals," Emerson Smith writes. In the 2008 report, for example, researchers noted that about 60% of 355 emerging infectious disease events that occurred over a 50-year period could be largely linked to wild animals, livestock, and, to a lesser extent, pets. Now, researchers believe the new coronavirus first jumped to humans from animals at a wildlife market in Wuhan, China.

Along those same lines, some experts have argued that global climate change has driven an increase in infectious diseases—and could continue to do so. A federally mandated report released by the U.S. Global Change Research Program in 2018 warned that warmer temperatures could expand the geographic range covered by disease-carrying insects and pests, which could result in more Americans being exposed to ticks carrying Lyme disease and mosquitos carrying the dengue, West Nile, and Zika viruses. And experts now say continued warming in global temperatures, deforestation, and other environmentally disruptive behaviors have broadened that risk by bringing more people into contact with disease-carrying animals.

Further, experts note that infectious diseases today are able to spread much faster and farther than they could decades ago because of increasing globalization and travel. While some have suggested the Covid-19 pandemic could stifle that trend, others argue globalization is likely to continue—meaning so could infectious diseases' far spread.

How can the world prepare?

Infectious disease and public health experts say there are ways the world can learn from the Covid-19 pandemic and prepare for the next emerging infectious disease—and hopefully stop it from becoming so widespread.

Beatrice Hahn, a professor of medicine at the University of Pennsylvania and an expert on HIV in chimpanzees, told Emerson Smith that researchers should "look at the natural reservoirs to see what's out there" and determine where zoonotic viruses first emerged to understand where they could be transmitted next.

Marion Koopmans—a professor and head of the viroscience department at Erasmus University Medical Centre in Rotterdam, the Netherlands—told ZME Science's Richard Gray that researchers should shift from having a reactive approach to addressing new infectious diseases to a proactive approach of trying to predict emerging infectious diseases and stop them from spreading.

"If we can rethink our models of disease detection, we can get ahead of that by ensuring we already have tests available and make sure there won't be a shortage of critical reagents we need for those diagnostic tests. We can make a start on looking for treatments and developing vaccines. But you can only do that if you are able to see these events coming," she said.