One Health Resource Center

One Health Resource Center

February 23, 2018
2 min read

WHO prioritizes ‘Disease X’ in R&D blueprint

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WHO recently released its annual list of priority diseases with an “urgent need” for accelerated research and development because of their potential to cause a public health emergency. Among them is an unknown disease that the agency termed “Disease X.”

“Disease X represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease, and so the R&D Blueprint explicitly seeks to enable cross-cutting R&D preparedness that is also relevant for an unknown ‘Disease X’ as far as possible,” WHO said in a statement.

Experts decided which diseases should be prioritized for R&D during a review earlier this month. They particularly focused on diseases that could impact special populations such as refugees, internally displaced people and disaster victims.

“WHO has been working to standardize the process and to engage experts from across the globe. Diseases are considered for inclusion if they have the potential to cause a public health emergency and if no medical countermeasures exist for that disease,” Inger Damon, MD, PhD, director of CDC’s Division of High-Consequence Pathogens and Pathology who participated in the WHO process as a CDC representative,” told Infectious Disease News. “At the end of the WHO meeting, there was consensus about the classification of diseases among the categories.”

In addition to “Disease X,” WHO’s list of priority diseases, which the agency said is not ranked in order of importance, includes:

  • Crimean-Congo hemorrhagic fever;
  • Ebola virus disease and Marburg virus disease;
  • Lassa fever;
  • MERS and SARS;
  • Nipah and henipaviral diseases;
  • Rift Valley fever; and
  • Zika.

Diseases the experts considered but did not include on the list were arenaviral hemorrhagic fevers other than Lassa fever; chikungunya; “highly pathogenic” coronaviral diseases other than MERS and SARS; nonpolio enteroviruses such as EV71 and D68; and severe fever with thrombocytopenia syndrome.

“These diseases pose major public health risks, and further research and development is needed, including surveillance and diagnostics,” WHO said. “They should be watched carefully and considered again at the next annual review.”

The agency also identified diseases that continue to pose a public health threat but are currently considered “outside of the current scope of the blueprint.” These included dengue, yellow fever, HIV/AIDS, tuberculosis, malaria, influenza-related illness, smallpox, cholera, leishmaniasis, West Nile virus and plague. Although all these diseases require R&D through existing interventions, there is a particular need for diagnostics and vaccines for pneumonic plague, as well as more effective therapeutics for leishmaniasis, according to WHO.

Disclosure: Damon reports no relevant financial disclosures.