Statistics are not everyone’s cup of tea. They can be complicated, bad actors can choose what they like, and sometimes they can tell us things we don’t want to know.
For example, a new statistical study has found that large pandemics are much more frequent than might be expected. In fact, the team found that a pandemic with a similar level of impact to COVID-19 has about a 2% chance of occurring each year.
When you add this over the course of a lifetime, it means that everyone has a 38% chance of experiencing a major one at least once and the odds seem to get worse over time.
“The most important takeaway is that big pandemics like COVID-19 and the Spanish flu are relatively likely,” said William Pan, a global environmental health researcher at Duke University.
The team examined the historical record of epidemics from the year 1600 to the present. They found 476 documented epidemics, about half of which had a known number of victims. About 145 caused less than 10,000 deaths, while another 114 we know existed, but not the number of deaths.
It is important to note that infectious diseases that are currently active were excluded from the analysis, so there is no COVID-19, HIV, or malaria.
The team used detailed models with a widespread distribution of Pareto to analyze the data, finding that the annual number of epidemics is immensely variable and that an extreme epidemic such as the Spanish flu of 1918-1920 was likely to occur between 0.3 and 1.9% each. for the last 400 years.
“The slow decline in probability with epidemic intensity implies that extreme epidemics are relatively likely to occur, a property not previously detected due to short observational records and stationary analysis methods,” the team writes in the paper.
But it’s not a constant probability either, it’s growing.
In the last 50 years, we have seen increasing levels of new pathogens spreading through humans. SARS-CoV-2 is the most obvious example, but even in recent decades we have had swine flu, bird flu, Ebola and many more.
“Along with recent estimates of increased rates of disease in animal reservoirs related to environmental changes,” the team writes, “this finding suggests a high probability of observing pandemics similar to COVID-19 (likelihood of experiencing in today’s life around 38 percent), which may double in the coming decades. “
Therefore, even as we recover from a current outbreak, it is important that we do not assume that we will not see another life-changing pandemic soon enough.
In fact, if we play our cards right, our response and resources for COVID-19 can prepare us for the next pandemic.
“This points to the importance of early response to disease outbreaks and capacity building for pandemic surveillance on a local and global scale, as well as to establishing a research agenda to understand why large outbreaks are becoming more frequent, ”Pan said.
If the statistics have anything to do with it, the next pandemic will come, we just hope we don’t forget the past.
The research has been published in PNAS.