Reviewing the Predictions of Epidemic and Pandemic Mortality: When Models Don't Align with Reality

Understanding Epidemiology Modeling

Epidemiology modeling is a valuable tool when it's impractical to observe and document all real interactions within complex systems. By simplifying the system into equations or probability-based distributions, we can generate results that may mirror what could happen in nature under certain circumstances. This method is not only more cost-effective but also quicker than conducting a long-term observational study across various epidemiological settings. However, the outputs of these models are more like a human-made painting than a film recording of a natural event. They depend entirely on the design of the program and the input parameters it's instructed to compute. While they can provide useful approximations of reality, they can also distort the viewer's perception, emphasizing certain aspects while downplaying others. This can trigger emotions or responses that direct observation might not evoke. Although these models can offer valuable insights, they are, at best, rough imitations of reality.

Challenges in Modeling Human Disease

The modeling of human disease becomes even more complex when it aims to predict rare events at a population level. The conditions and responses that either promote or mitigate diseases fluctuate greatly over time. Infectious diseases used to be a leading cause of death among children under 10, but mortality rates have significantly decreased in wealthier countries, thanks to improvements in hygiene, living conditions, nutrition, and the introduction of antibiotics. Therefore, using historical events to predict current health risks would be akin to assessing the safety of modern air travel based on the performance of the Wright brothers' initial airplane designs.

The Increased Emphasis on Outbreak and Pandemic Risks

Despite a steady global reduction in infectious disease mortality over the past 30 years, there has been an increased focus on the risk of outbreaks and pandemics, especially since the onset of the Covid-19 pandemic. This concern has led to calls for unprecedented funding and a major reorientation of several international health agencies. A 2024 report by the REPPARE project at the University of Leeds, titled "Rational Policy Over Panic," revealed that several key international agencies involved in pandemic prevention, preparedness, and response (PPPR) policy development had misrepresented the risk. This was primarily due to a failure to consider advances in healthcare and technological developments for detecting and recording disease outbreaks.

Reviewing Public Health Response and Future Pandemic Risk

With the acute phase of the Covid-19 pandemic over, many countries are now evaluating their public health response and how future pandemic risk should be prioritized and addressed. Member States of the World Health Organization are discussing the proposed Pandemic Agreement and acceptance of recent amendments to the International Health Regulations. Meanwhile, several new PPPR institutions have been established, including a new Pandemic Fund, International Pathogen Surveillance Network, and a Medical Countermeasures Platform.

The Role of Predictive Modeling in Assessing Pandemic Risk

Predictive modeling by Metabiota, a company now part of Ginkgo Bioworks, has significantly influenced the conversation on pandemic risk and the need for increased funding. The company's modeling was one of two primary sources for risk assessment in the G20 High Level Independent Panel (HLIP) report in June 2021. This report played a crucial role in shaping the G20 Group of Nations' support for the WHO's PPPR agenda. Ginkgo Bioworks has now provided a more detailed report to the New Zealand Royal Commission on COVID-19 Lessons Learned, titled "Estimated Future Mortality from Pathogens of Epidemic and Pandemic Potential."

The Bioworks Report: Predicting Epidemic and Pandemic Threats

The Bioworks report aims to predict the threat of epidemics and pandemics to human health. It uses computational epidemiology and extreme events modeling simulations to estimate mortality from "low frequency, high severity" epidemics and pandemics, particularly those caused by respiratory diseases. The report concludes that an average of 2.5 million deaths are attributable annually to these acute respiratory outbreaks. Many find these results hard to believe, as there hasn't been such an annual influenza mortality in a century. The report also estimates an average of 26,000 global deaths from viral hemorrhagic fevers (VHFs), which is higher than any previously recorded year.

Overlooking Crucial Factors

The model used in the Bioworks report overlooks two major factors. First, it fails to consider the societal and medical changes over the past several hundred years that have seen global life expectancy rise from below 30 years to over 70. Second, it doesn't account for the advent of modern diagnostics and the improved ability to record and transmit such information.

The Influence of Modeling on Policy Development

Modeling of this type has become highly influential in policy development. However, a model with unrealistic assumptions and input parameters will simply reach an implausible outcome more quickly. While modeling can help raise questions for serious research, when misused or overemphasized as a policy guide, it can divert resources from real disease burdens to hypothetical ones. This could lead to increased mortality, as outcomes of current high-burden endemic infectious diseases remain highly dependent on the availability of official development assistance (ODA, or 'foreign aid').

Bottom Line

Technological advances have contributed to the reduction in infectious diseases, including pandemic mortality. However, the misuse of technology through inappropriate use of models could undo many of these important gains. It's crucial to remember that we should not assess the probability of surviving future pandemics based on the era of Medieval medicine. What are your thoughts on this topic? Do you agree with the points raised in this article? We encourage you to share this article with your friends and engage in a discussion. You can also sign up for the Daily Briefing, which is available every day at 6 pm.