Another major pandemic is likely to occur this century, scientists warn

Researchers warn that the next major pandemic may not be so far away. In a new article published on Monday, they estimate that a pandemic as deadly as covid-19 is expected to happen over the next six decades, while a pandemic of the magnitude of the Spanish flu of 1918 is expected to recur every 400. years. They also argue that the annual likelihood of these extreme events may increase over time, as emerging and re-emerging diseases have become more common in recent decades.

The world is currently in the second year of the covid-19 pandemic, which has so far kill at least 4.4 million people and probably many more. Apart from HIV / AIDS, which has killed at least 36 million since its emergence in the 1980s but not always considered a pandemic, covid-19 is the deadliest pandemic since the Spanish flu, which killed between 20 and 100 million people (most estimates revolve around 50 millions).

However, pandemics are not as rare as some might think. The last pandemic before covid-19 was only a decade earlier – the 2009 swine flu – and one pandemic has occurred on average every 20 years for the past century. But researchers at Duke University and elsewhere say there hasn’t been much statistical work done to estimate the likelihood of these large disease outbreaks – a knowledge gap they hoped to fill in their new one. article, published Monday in the journal PNAS.

“First of all, I have to say that we don’t make predictions about the future. We are characterizing the likelihood of large epidemics occurring based on historical data, ”study author William Pan, associate professor of global environmental health at Duke University, told Gizmodo.

The team looked at major recorded epidemics of plague, cholera, new strains of influenza and other pathogens, dating back 350 years, to make their estimates. They especially focused on epidemics of emerging or re-emerging diseases that have killed at least 10,000 people. They crushed together epidemics that occurred in different places around the same time, such as simultaneous plague outbreaks in the 17th and 18th centuries. And they also ruled out disease outbreaks after they became manageable by drugs like antibiotics or vaccines, as well as ongoing epidemics like HIV / AIDS, malaria and covid-19 (in practice this meant that no epidemics after 1945 were included in their main analysis) .

Overall, there was a lot of variation in the frequency with which major outbreaks occurred over the years, although they declined over time. But the team says their new statistical modeling method, previously used to estimate the risk of extreme weather events, such as flooding, can determine an approximate probability of the likelihood of pandemics of varying scale occurring on an annual basis. For something like covid-19, they estimate that the probability of a covid-like event occurring in any given year is now around 2%, which means it is expected to occur within the next 59 years. Importantly, it doesn’t mean that the next covid is in 59 years, just that in 59 years we should see it happen again. For something like the Spanish flu, they say something similar should happen every 400 years, plus or minus a few decades.

According to other research, Pan said, the likelihood of a pandemic should decrease significantly the more severe it is (so a Spanish flu event should be extremely rare). But his team’s work seems to show that this likelihood does not decrease as quickly relative to severity, so even catastrophic pandemics can occur with alarming regularity.

The work behind the team’s math is based on assumptions, as are all models. So in the end, these numbers are just estimates. But the authors argue that their baseline predictions may underestimate the problem, if at all. They point out that small-scale epidemics of emerging and re-emerging diseases have increase over the past decades. And when they factored this increase into their modeling, they concluded that the annual probability of extreme epidemics could triple in the coming decades. This could mean that a pandemic of the magnitude of the Spanish flu would occur every 127 years on average, not 400.

While the team hasn’t investigated why these outbreaks are becoming more frequent, Pan cites other research showing that environmental changes have led to more contact between humans and animals that may be carriers of these exotic germs. . Poverty, lack of sanitation and the lack of good health care systems can then allow diseases to continue to spread, as can the lack of cooperation between countries to monitor these threats.

The basic message here is that large-scale pandemics are relatively likely to occur, according to the authors. And because of that, we should be doing more to prevent them or mitigate their impact when they arrive. “We’re obviously showing the potential threat of global pandemics, but the real implication here is how to invest more effectively in global health and pandemic preparedness? Pan said.

Pan said scientists should study the ongoing global response to covid-19, to determine which approaches should be taken or avoided in the future, while acknowledging that some interventions may not work for all future threats. pandemic (masks may not be needed, for example, depending on how the hypothetical pandemic spreads). We also need more teamwork between countries, ideally aided by existing structures like the United Nations and the World Health Organization.

“But it’s not just an emergency response – it’s also about picking up the poorest and most vulnerable countries – we have to make sure we meet the Sustainable Development Goals,” said Pan, referring to the UN plan to reduce the impact of extreme poverty, inequality and other major threats like climate change by 2030.

Their calculations on the likelihood of the Big One, a pandemic deadly enough to end humanity, are not included in the team’s document. But they created such an estimate: According to their model, a pandemic that could kill all humans is likely within the next 12,000 years. On the bright side, there are plenty of other things that could kill us all before that, like a asteroid, artificial superintelligence, Where nuclear holocaust.