Another pandemic like COVID-19 is all but guaranteed, health experts say. Whether it happens next year or a decade from now, these massive public health emergencies are of course happening regularly, especially as our world gets warmer due to climate change and more viruses and other pathogens spill over from our dwindling wilderness.

The World Health Organization (WHO) keeps a list of the bacteria, fungi, viruses and parasites most likely to cause havoc, and recently updated its list of the world’s most threatening pathogens. It did so with the help of over 200 scientists from more than 50 countries who examined data from more than 1,600 viruses and bacteria. And as it turns out, there are more germs of concern than previously thought.

In the report released last week, the WHO updated the list to more than 30 pathogens that could cause another pandemic and added new ones – namely the influenza A virus, dengue virus and Mpox virus. A notable addition to the list is the Mpox virus (formerly known as “monkeypox”), which caused a global pandemic in 2022. But the virus is constantly mutating and a more deadly strain is now spreading rapidly in Africa. This week it was reported that the WHO is considering declaring a “public health emergency of international proportions” in light of the looming crisis.

The authors of the report also warn of Pathogen X, a previously unidentified pathogen that could cause major health problems in the future.

“Pathogen X is a term that refers to an unidentified or unspecified pathogen,” the authors write. “Unknown pathogens with the potential to cause a (public health emergency of international concern) or pandemic in the future. It is difficult to predict the specific pathogen that may lead to the next (public health emergency of international concern) or pandemic. Although there are numerous viruses and bacteria that can infect humans, only a limited subset have been responsible for pandemics or widespread epidemics in the past.”

While the WHO report may seem alarming, it’s hard to prepare for the next pandemic if we don’t know what to look for. This “most wanted” list is a good place to start.