What’s Disease X? World leaders discuss next possible global health threat

Disease X, a hypothetical illness with the potential for 20 times more fatalities than the COVID-19 pandemic, was the focal point of a panel discussion in Davos, Switzerland, on Wednesday, where international leaders gathered to deliberate on the potential looming threat.

The World Economic Forum held a meeting Wednesday morning called Preparing for Disease X, with a panel of speakers including the World Health Organization (WHO) and pharmaceutical company AstraZeneca, that were pegged to discuss “what novel efforts are needed” to prepare the health-care system for the potential challenges ahead.

“Disease X represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease,” the WHO states on its website. The goal is to be prepared as much as possible for an unknown “Disease X,” it added. 

“Disease X is a hypothetical scenario where a very nasty disease, which is more powerful than COVID-19, emerges,” explained Kerry Bowman, a professor of bioethics and global health at the University of Toronto.

“It is the preparation for a hypothetical situation in terms of how the entire world would respond to a rapidly emerging disease threat.”

During the panel discussion in Davos, WHO Director-General Tedros Adhanom Ghebreyesus stressed the need to have “a placeholder for diseases we don’t know” to be adequately prepared for their arrival, and shot back at criticisms of those discussions.

“Of course there are some people who say: ‘Oh, this may create panic,’” Tedros said. “No. It’s better, actually, to anticipate something that may happen – because it has happened in our history many times – and prepare for it.”

Although preparation is a great tool, Bowman worries that prevention has not been highly discussed, especially since the COVID-19 pandemic broke out. He believes the greatest Disease X threat would be zoonotic, which means a disease that emerges in an animal.

An example of a zoonotic disease is the H1N1 influenza virus, commonly known as swine flu.

“And with the amount of animals that are being decimated around the world and the amount of loss of forest, we’re opening up that threat more and more,” he said. “One of the concerns I have is: does it not make more sense to focus on prevention as well as preparation?”

Approximately 1.67 million undescribed viruses are thought to exist in mammals and birds, up to half of which are estimated to have the potential to spill over into humans, according to a 2021 study published in the Indian Journal of Medical Research.

The risk of the emergence of these yet-to-be-identified threats grows larger with increasing human population, loss of biodiversity, changing climates, aggressive land use for human habitation and agriculture, all of which contribute to the expanding interfaces between humans, animals and the environment, the authors state.

The most recent example is the novel coronavirus, SARS-CoV-2, which started spreading globally in late 2019. The virus has since infected hundreds of millions of people and resulted in more than 6.8 million deaths worldwide, according to the latest data collected from Johns Hopkins Coronavirus Resource Center.

How the coronavirus initially began affecting people remains unclear. However, international scientists who examined previously unavailable genetic data from samples collected at a market close to where the first human cases of COVID-19 were detected in China said they found suggestions the pandemic originated from animals, not a lab.

Recognizing the importance of emerging infectious diseases (EIDs), the WHO first highlighted Disease X as a target for research and development back in 2018.

“Disease X has been getting a lot of attention but it’s not a new idea,” Tedros said Wednesday. “The first time we used the terminology was in 2018.”

Because of this lingering threat, WHO gave this unknown future outbreak a placeholder name in its R&D Blueprint: Disease X.

“Although COVID came immediately, we were preparing for a COVID-like disease,” Tedros said. “You may even call COVID … the first Disease X. And it may happen again.”

The 2018 document lists the illnesses that the WHO believes could pose a serious risk to public health, such as the Ebola virus, the Zika virus and severe acute respiratory syndrome (SARS).

Bowman suggested that, given the global shortcomings in planning for COVID-19, particularly in safeguarding vulnerable populations, it is essential to examine the lessons from COVID-19 before embarking on preparations for future pandemics.

“I don’t see how we can prepare for the future without dealing with the past. It just doesn’t make sense to me,” he said. “Disease X is a preparation for the future and I don’t see how we do that without taking stock of what we’ve learned so far. There’s a piece missing there.”

For example, he said we made “a lot of mistakes” within our own country, particularly in the long-term care of older adults.

“We really did very little to protect them,” Bowman said.

In July 2023, the BMJ medical journal called for an independent inquiry into Canada’s COVID-19 response. In a series of articles, experts from 13 organizations across Canada, including doctors, nurses, researchers, and law and humanitarian specialists, wrote about the shortfalls in Canada’s COVID-19 response. This included difficulty reaching vulnerable and marginalized populations who were most at risk, the catastrophic deaths in long-term care homes and inconsistent public health messages across provinces and territories.

2:22 New report exposes failures in Canada’s long-term care homes during first wave

“Lessons from a previous outbreak of, SARS-CoV-1 — which in 2003 impacted more Canadians than anywhere else outside of Asia— went unheeded and left the country’s governments and health authorities ill-prepared for COVID-19,” one of the articles states.

The articles also acknowledge successes in Canada’s pandemic response, including a vaccination rate of more than 80 per cent.

Bowman expressed concern that little progress has been made in terms of future preparedness and prevention since the onset of COVID-19. He suggested the potential implementation of surveillance measures and homemade vaccines.

“A lot of Disease X talks tends to be how we can get vaccines out there the fastest way possible,” Bowman said. “But what did we learn from COVID-19 and how will that inform planning for Disease X?”