27 December 2021

COVID-19, as terrible as it has been, is far from the worst infectious disease pandemic imaginable. A hundred years ago, the world was hit by a flu pandemic caused by a virus that was four to five times more lethal than COVID-19. And in this century alone we’ve already suffered outbreaks caused by coronaviruses (SARS and MERS) that are respectively around 20 and 70 times as lethal as SARS-CoV-2.  The only thing that prevented a catastrophe of unfathomable proportions was that they lacked the transmissibility of COVID-19.

Vaccines are at the heart of how modern societies counter infectious disease threats. They are our most potent tool against pandemic risks and will be critical to any future response. The faster an effective vaccine is developed and deployed, the faster an incipient pandemic can be contained and controlled. 

The aspiration of the Coalition for Epidemic Preparedness Innovations (CEPI) is for the world to be able to respond to the next “Disease X” with a new vaccine in just 100 days. That’s a little over three months to defuse the threat of a pathogen with the potential to cause a pandemic. Coupled with improved surveillance providing early detection and warning, and with swift and effective use of non-pharmaceutical interventions, delivering a vaccine in 100 days would give the world a fighting chance to extinguish the existential threat of a future pandemic virus.

The X in “Disease X”  stands for everything we don’t know. It's a new disease, about which we will know very little when it first emerges: it may or may not be deadly, highly contagious and a threat to our way of life. We also don’t know when or how it will come across the viral frontier and infect people. What we do know is that the next Disease X is coming and that we have to be ready.

Prepare to Prevent

Before the SARS-CoV-2 virus emerged, the previous vaccine-development record was for a live attenuated mumps vaccine, which took a little less than 5 years. By comparison, the 326 days it took from the SARS-CoV-2 virus being identified to bringing a COVID-19 vaccine into emergency use represented a quantum leap. With tightening and shortening at each development stage, and by rethinking how we establish safety and efficacy for emergency response vaccines, cutting that timeline to 100 days is entirely feasible.

It’s all about being properly prepared.

Scientifically, it’s about making advances across the whole life cycle of pandemic preparedness—from the moment a new pathogen is identified, through the rapid prototyping of a vaccine candidate, through the testing and authorization of that vaccine to get it into to the arms of people at risk.

Economically, it’s about being prepared to make large, bold investments to speed up the building of our defences against emerging threats, even when those investments might not pay off.

Politically it’s about recognizing the scientific opportunity, accepting the moral obligation to try, and crucially, making it work for everyone, not just those fortunate enough to be born in wealthy countries.

The Next Disease X—It’s “When”, Not “If”

Pathogens continually emerge and re-emerge: from human monkeypox and drug-resistant malaria to typhoid and plague, the deadly Nipah and MERS viruses, the frightening strains of bird flu, and the mosquito-borne Zika and Chikungunya viruses. Not all new diseases have pandemic potential, but the next one that does could be as bad as COVID-19, if not worse.

There are around 260 viruses—belonging to roughly 25 viral families—known today to be able to infect humans. Realistically, we can’t create individual new vaccines against several hundred or more potential or developing threats, let alone the 1.6 million or so more viral species that may exist in mammal or bird hosts and have yet to be discovered, but we can develop vaccines against prototypes of these threats. In other words, we can focus our efforts on pathogens that exemplify some or all of the worst traits of a particular viral family.

Dr. Richard Hatchett. ©CEPI

In many ways, COVID-19 is a proof of concept for the “prototype vaccine” approach to rapidly developing vaccines against new viral threats.

For several years before the emergence of SARS-Cov-2, scientists were already working on vaccines against MERS and SARS, pathogens from the same virus family as COVID-19. What they learned enabled them to pivot quickly and respond at lightning speed to the new virus, laying the groundwork for the record-breaking effort to develop COVID-19 vaccines. 

Also important in the story of COVID-19 vaccine development were the extraordinary leaps forward in vaccine technology that came to fruition at precisely the right moment.

For years before SARS CoV-2 emerged, scientists had been honing so-called rapid-response platforms to make “plug-and-play” vaccines. Some used mRNA technology, and others, like the University of Oxford’s ChAdOx, used viral vectors. This meant that when Disease X came, and was identified and named as SARS CoV-2, vaccine makers could plug in the genetic code for a part of the novel coronavirus that would trigger an immune response. 

As part of helping the world prepare to prevent future pandemics, the CEPI plan is for scientists to create a range of vaccine candidates for each viral family and then select a handful as prototypes to put through rigorous testing, including safety and dosing trials in people.

In this way, when a newly emerging virus comes across the frontier—and that is most certainly a “when” and not an “if”—we’ll have banked a vast amount of data on safety and immunogenicity of both the plug-and-play platform technology and the antigens of viruses that are closely related, if not exactly the same, as the new Disease X.

Ultimately, the speed gains made through global surveillance and early detection and alerting, coupled with earlier suppression efforts, should mean that case numbers in any new Disease X outbreak might still be relatively small. And with a vast library of knowledge built up, inserting a genetic sequence for a new and threatening Disease X means we’ll already be months ahead in constraining not just the outbreak and the novel virus, but crucially, its pandemic potential.

Invest Now to Save Later

If there’s one thing we found out during the COVID-19 crisis, it’s that pandemics are devastatingly expensive. By the end of 2025, it is forecast that COVID-19 will have cost the world $28 trillion over 5 years. The human cost is something we will never be able to quantify, but its effects will no doubt reverberate for generations.

Being properly prepared doesn’t come cheap. Creating the vaccine library could mean developing as many as 100 prototype vaccines to ensure we’ve got something in the knowledge bank to help us cover almost any threat. That’s a lot of work, but it’s finite. It’s also eminently achievable if governments and industry work together. For its part, CEPI has a $3.5 billion pandemic-busting plan that, over the next 5 years, will kickstart and coordinate this work. Compared with the trillions lost to COVID-19, at $3.5 billion this plan is not only value for money, it’s exactly what the world needs to ensure that our children never again face the hardship and loss we’ve had to endure from COVID-19.


The UN Chronicle is not an official record. It is privileged to host senior United Nations officials as well as distinguished contributors from outside the United Nations system whose views are not necessarily those of the United Nations. Similarly, the boundaries and names shown, and the designations used, in maps or articles do not necessarily imply endorsement or acceptance by the United Nations.