World Health Organization (WHO) compile a list of "priority diseases" which in the future could cause the next pandemic, he writes New York Post.

Most of the diseases on that list are already known to us - Ebola, SARS, Zika and so on – but the last disease on that list has a terrifying name "disease x".

The term "disease X" is used by the WHO to reserve a place on the list for a disease currently unknown to medical science that will cause infections in humans.

Since the cause of the disease – a virus, bacteria, fungus or something else – will still be unknown, there will likely be no vaccines or cures available.

"This is not science fiction. This is a scenario for which we must prepare. It's 'disease X,'” says Dr. Richard Hatchett of the Coalition for Epidemic Preparedness Innovations (CEPI).

CEPI was founded in early 2017 by the governments of Norway and India, the Bill & Melinda Gates Foundation, the Welcome Trust and the World Economic Forum and is a partnership between public, private, philanthropic and civil society organisations. CEPI's mission is to fund and coordinate the development of vaccines to protect the world from future epidemics.

One of the ways CEPI intends to do this is by supporting the development of "platform technologies" that will accelerate the production of vaccines against new and unknown pathogens such as the predicted "Disease X".

As for the term "disease X" itself, it was coined by the World Health Organization in 2018. By including the disease in the list of priority diseases, the WHO warns of the risk of some new, still unknown pathogens.

The same year, in British "Telegraph" an article appeared by Dr. Hatchett in which he describes the reappearance of the ebola virus in Africa, which is now much easier to control because we know it and there are vaccines and drugs.

"But imagine a virus that we've never seen before, for which there is no cure, and which could threaten thousands, maybe even millions of people around the world. Aside from the lives of those affected, imagine what effect that would have on the world economy?” asked Dr. Hatchett in the article.

But it didn't take long to imagine.

A year later, when covid-19 began to spread across China, the world witnessed a deadly pandemic caused by the new virus. At that point it was "Disease X."

"It is no exaggeration to say that there is a possibility that 'Disease X' will emerge very soon," said Dr. Pranab Chatterjee, a researcher in the Department of International Health at the Johns Hopkins Bloomberg School of Public Health in Baltimore. "The recent wave of H5N1 bird flu in Cambodia is just an example," Chatterjee added.

Some public health experts believe that the next "Disease X" will be zoonotic, which means it will originate from wild or pets, and then it will go to the people.

Ebola, HIV/AIDS and covid-19 were zoonotic diseases.

However, there are other sources of the disease, and one of them may be in the future bioterrorism.

"We do not ignore the possibility of a manufactured pathogen," say the authors of the article published in 2021.

"The spread of such pathogens, either by accidental laboratory accidents or their deliberate release, could cause 'Disease X' and have catastrophic consequences," they added.

There is another possibility to work on the n. "zombie viruses" which were frozen in permafrost for centuries, but are now being released due to climate change and melting ice.

Some of the priority diseases on the WHO list are Marburg virus, Crimean-Congo hemorrhagic fever, Nipah and other henipaviruses, Rift Valley fever and MERS.

In order to prevent or combat the imagined "Disease X", medical experts are calling very loudly for increased investment in surveillance and research of viruses with pandemic potential.

"Covid-19 was not the first epidemic to cause many problems in the world, and it will not be the last," wrote the authors of the article in the journal "Infection Control & Hospital Epidemiology." "That is why we must prepare for the outbreak of the next pandemic as soon as possible."