New Deadly Pathogen - 'Disease X' added to WHO Watchlist

This year’s list from the World Health Organization has a remarkable new addition: “Disease X”. (Photo: Pixabay)

For the purposes of the R&D blueprint, the World Health Organization (WHO) has developed a special tool for determining which diseases and pathogens to prioritise for research and development in public health emergency contexts. The blueprint is an attempt to improve communication, coordination and funding, quicked research and development, and to develop countermeasures that will shorten the time from an outbreak to the time that vaccines are available. On this year’s list, there’s a remarkable new edition, “Disease X”. 

“These diseases pose major public health risks, and further research and development is needed, including surveillance and diagnostics,” the WHO explains in a statement. “Disease X represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease.” The intention behind listing X is to motivate crosscutting research and development efforts for well-known diseases that would be relevant for an unknown disease. 

Rapid advances in gene editing technologies, like CRISPR-Cas9, means that “Disease X” could emerge from an accident or even an act of terror, while another possible source could be a disease arising through human-animal interaction. 

“History tells us that it is likely the next big outbreak will be something we have not seen before. It may seem strange to be adding an ‘X’, but the point is to make sure we prepare and plan flexibly in terms of vaccines and diagnostic tests. We want to see ‘plug and play’ platforms developed which will work for any, or a wide number of diseases — systems that will allow us to create countermeasures at speed,” John-Arne Rottingen, Chief Executive of the Research Council of Norway and Scientific Adviser on the WHO committee, told the Telegraph. 

Although a man-made “Disease X” is less likely than a naturally occurring disease, Rottingen still warns: “Synthetic biology allows for the creation of deadly viruses. It is also the case that where you have a new disease there is no resistance in the population and that means it can spread fast”. 



  • Crimean-Congo haemorrhagic fever (CCHF)
  • Ebola virus disease and Marburg virus disease
  • Lassa fever
  • Middle East respiratory syndrome coronavirus (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS)
  • Nipah and henipaviral diseases
  • Rift Valley fever (RVF)
  • Zika
  • Disease X 

*Diseases posing significant risk of an international public health emergency for which there is no, or insufficient, countermeasures. (WHO, 2018)