World Health Organization (WHO) Director-General Tedros Ghebreyesus has issued a new warning about the likelihood of Disease X breaking out, telling global world leaders it is "a matter of when, not if" a new pathogen and pandemic will strike.

Tedros, who goes by his first name and is not a medical doctor, told attendees at the World Government Summit in Dubai earlier his week he gave a similar warning in 2018 that a pandemic was likely to hit, and he was proven right with the outbreak of the deadly coronavirus.