Disease X is a placeholder name for an “unexpected” disease. The World Health Organization declared in 2018 that Disease “X” was a hypothetical unknown pathogen that could cause an epidemic. COVID-19, caused by the virus SARS-CoV-2 is the first to meet the requirements of a ‘Disease X.’
Deeper dive
When infectious disease experts are asked about what the next pandemic might be, they often answer “Disease X.”
Disease X stands for an unknown bacteria, or virus that might be lurking in animals or humans, with the potential to suddenly become virulent and contagious, spreading around the world, just as occurred with SARS-CoV-2 and COVID-19 at the end of 2019.
“Disease X” was named in 2018 by the World Health Organization as one of nine diseases that public health officials believe is of high risk to blow up into an epidemic. The WHO list, called the “Blueprint Priority Diseases,” was developed to spur research investment in finding vaccines, treatments and medical counter measures for these pathogens, where few or none currently exist.
On the list includes COVID-19, Crimean-Congo hemorrhagic fever, Ebola and Marburg virus disease, Lassa fever, Middle East Respiratory syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS), Nipah and henipaviral diseases, mosquito-borne diseases Zika and Rift Valley Fever, and Disease X.