Do I need to worry about Disease X? Here's what experts say about the threat posed by unknown future pandemics.

The ominously-named “Disease X” isn’t an actual disease (yet). But it’s gaining attention online as experts look beyond COVID-19 to future public health threats.

What's happening

Disease X is a term that was created years ago, and the World Health Organization started including it on its list of priority diseases in 2017 alongside familiar diseases like Zika and Ebola. It’s used as a placeholder for new, yet-to-be-discovered threats, with WHO writing that “Disease X represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease.”

COVID-19, caused by the then-new SARS-CoV-2 virus, was an example of a Disease X when it first emerged at the end of 2019.

Do I need to worry?

“It is definitely something to worry about, and it is not a matter of if we're going to have another pandemic — it's a matter of when,” Pablo Penaloza-MacMaster, an assistant professor of microbiology-immunology at Northwestern University Feinberg School of Medicine, tells Yahoo Life of the threat posed by undiscovered pathogens and future pandemics.

There was more than a 100-year gap between the COVID-19 pandemic and the 1918 Spanish Flu pandemic, but experts say it likely won’t be that long between pandemics in the future, for a number of reasons:

• Population growth: A larger, denser global population gives pathogens more susceptible hosts and more opportunities to jump from person to person.

• More travel: People are traveling farther and with more ease than ever before — which facilitates the spread of diseases.

• Global warming: Climate change is worsening the spread and severity of infectious diseases and could also lead to the reemergence of ancient viruses as permafrost melts.

• Deforestation and encroachment on wildlife: By destroying and invading animals’ natural habitats, we’re blurring the boundaries between humans and animals — giving viruses and other pathogens that previously only infected animals more opportunities to jump to human hosts.

“We've learned the hard way from COVID-19 the ramifications of not being prepared,” Dr. Wafaa El-Sadr, an epidemiology professor at Columbia's Mailman School of Public Health and lead of the New York City Pandemic Response Institute, tells Yahoo Life. “So I think it behooves us to anticipate and prepare for a potential next pandemic that may come down the line.”

What can we do about it?

There are several major steps we can take to be prepared for a Disease X.

• Invest in science. Experts emphasize the need for more investment in science and research now — before the next pandemic hits. “What enabled us to produce vaccines so rapidly for SARS-CoV-2 is that there had been work on the technology ongoing for years and years,” El-Sadr says. “The work didn't start the day SARS-CoV-2 was identified; it started years before.” Penaloza points out that while the U.S. spends around $800 billion annually on the military, the National Institutes of Health, which funds research around the world, receives around $45 billion per year. “We need to invest more in improving our arsenal against infectious disease,” he says.

• Do more surveillance and sequencing of viruses. El-Sadr suggests putting in place systems to do better in terms of surveillance of disease, collecting data and sharing data. “One possibility could be doing more surveillance and sequencing more viruses in animal reservoirs — going out to the field and identifying new viruses, getting the sequences and then preemptively making vaccines based on those known sequences,” Penaloza says. “And then when there's a new pandemic, you could think about potentially deploying the most matched vaccine, the one that matches or corresponds better to the sequence of the future pandemic.”

• Increase public awareness and education. Confusing messaging and poor communication of information was a problem especially at the beginning of the COVID-19 pandemic. El-Sadr says keeping the public informed about the science and public health threats is a good way to prepare for the next pandemic at a community level.

• Build more equitable health care systems. Equity was also an ongoing problem during COVID-19, with the most vulnerable — and particularity communities of color — having a harder time accessing tests, vaccines and treatments. “The lesson learned from COVID-19 is that we have to have a better streamlined health delivery system, rather than currently the very siloed delivery of health services, and to work very hard at trying to have equitable and high-quality services for everyone,” El-Sadr says.

The main takeaway

Penaloza says that despite high death tolls and hospitalizations, we actually got relatively lucky with COVID-19; SARS-CoV-2’s genetic sequencing was just similar enough to other known coronaviruses that we could develop vaccines fairly quickly.

“Even though it was a tragedy in some aspects, there was a lot of background information that could be used,” he says.

There’s no guarantee that Disease X will be as familiar next time around. But while we may have more knowledge and experience under our belt since the COVID-19 pandemic, “anti-science movements” and growing vaccine hesitancy are obstacles public health officials will have to tackle as we prepare for future diseases.

“I wish I could say that we are prepared, but I do think we have a ways to go,” El-Sadr says. “I think we've learned a lot of lessons from COVID-19, but unfortunately often people forget, or they want to put it behind them, or there's this sense of, 'This can't happen again in the near future.’ There's a complacency that sets in, and that's the worst thing that you can do in terms of trying to be prepared.”