8. Can pandemics be predicted?

Planning and preparing for pandemics are tasks that should be carried out by national governments and international organizations. The WHO writes recommendations and guidelines, although there is no organized system implemented worldwide to review how prepared the different countries are for epidemics, or to measure their rapid response abilities.

The COVID-19 pandemic revealed that several wealthy nations healthcare systems were not prepared and were completely overwhelmed, due to lack of equipment for intensive care, beds and other medical needs. Indeed, shortages were expected to occur even earlier on in the pandemic. The World Health Organization (WHO) and the World Bank warned about the risk of pandemics throughout the 2000s and 2010s, especially after the 2002–2004 SARS outbreak. In 2018, the WHO coined the term, Disease X, which “represents the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease” in order to focus research and development on likely candidates for the next unknown pandemic. International divisions and a lack of suitable collaboration limits preparedness.

A number of organizations have been involved for years in preparing the world for epidemics and pandemics, trying to produce a platform for dealing with emerging epidemic disease such as COVID-19, which would enable rapid vaccine development and immunity research in response to outbreaks. Since several centuries, scientists have become increasingly better at interpreting many aspects of the world, including the orbit of planets, the ebb and flow of tides and the paths of hurricanes. The ability to understand natural and physical systems well enough to make accurate forecasts is perhaps one of humanity’s greatest achievements.

There are limits, however, in predicting when the next disease outbreak will happen, because the most important variables can change significantly from one outbreak to another.

Infectious disease is caused by a transmissible pathogen. The infectiousness of that disease can be summarized in a number called the “basic reproductive ratio,” or R0, a number describing how widely a pathogen is likely to spread in a given population.

If epidemiologists know enough about a pathogen’s R0, it is hoped that they can predict aspects of its next outbreak – and possibly prevent small-scale outbreaks from becoming large-scale epidemics. They could achieve this by mobilizing resources to areas where pathogens have especially high R0 values or by limiting interactions between the carriers of disease and the most susceptible members of a given society, often children and the elderly.

The features of an epidemic – the pathogen’s contagiousness, rate of transmission, the availability of vaccines and so on, change rapidly during the course of a single outbreak. Epidemics are often not precise phenomena but complex scenarios where many variables play essential but shifting roles. There is no underlying truth about a disease – only an unstable collection of details that vary, often becoming entangled, as the disease spreads.

Disease surveillance remains a high-stakes area of science. Careful consideration for unique circumstances causing outbreaks, and more responsible collection of data, could save countless lives.