How to Think Clearly About Mystery Disease Outbreaks?

Not every scary disease headline means the next pandemic is here. Here are four questions to ask.

Every few months, my social media feed fills up with scary headlines about a “mystery disease” or a possible new pandemic. A few weeks ago, it was reports out of Russia — people coughing up blood, testing negative for common viruses, and speculation that this might be a new, unknown pathogen.

This kind of story has become so common that I think we’re now facing something like an “epidemic of epidemic rumors.” But there’s a way to think more clearly when these stories pop up.

Questions to Ask About Any New Outbreak

When I worked at CDC, the very first thing we learned about investigating outbreaks was this: start by confirming the facts.

Whenever I hear about a potential new disease — whether it’s called “Disease X” or something else — I run through four key questions:

1. Has the disease actually been confirmed in a lab?

Early reports are often based on symptoms like fever, cough, or diarrhea — which can be caused by dozens of well-known infections. Until specimens are collected and tested (ideally in a good lab), it’s impossible to know whether this is something new or just something familiar showing up in a new place.

2. How is it spreading?

Airborne transmission — meaning the infection passes from one person’s breath to another — is the most concerning. But if transmission requires direct contact, contaminated food or water, or insect bites, the outbreak is much less likely to explode globally.

3. How severe is it?

Paradoxically, diseases that kill quickly and severely (like Ebola) often spread less easily than milder diseases like COVID-19 or measles, which allow infected people to walk around and unknowingly infect others.

4. Do we have tools to fight it?

Our concern becomes less if we have drugs that can reduce symptoms, reduce infectiousness, and/or cure disease. Similarly, we can be less worried if we have vaccines that can prevent severe illness and reduce infectiousness. If we have neither drugs nor vaccines, we need to be more worried.

Bottom Line

Most reports of “mystery illnesses” or “Disease X” turn out to be something we already know how to deal with — like malaria, flu, or a seasonal virus.

That doesn’t mean we should ignore them. It just means we should approach these stories like a public health detective — looking for facts, not just fear.

Read more: https://www.healthbeat.org/2025/04/09/disease-x-outbreak-how-to-assess-reports/