WEDNESDAY, Aug. 25, 2021 (HealthDay News) -- Major pandemics aren't all that rare and they're likely to occur more often in the future, a new study claims.
"The most important takeaway is that large pandemics like COVID-19 and the Spanish flu are relatively likely," study co-author William Pan said in a news release from Duke University, where he is an associate professor of global environmental health.
That points to the need to boost efforts to prevent and prepare for them, the researchers emphasized.
Their analysis of disease outbreaks worldwide over the past 400 years -- including plague, smallpox, cholera, typhus and new influenza viruses -- showed that the probability of a pandemic on the same scale of COVID-19 is about 2% in any year.
That means that a person born in the year 2000 would have about a 38% chance of experiencing one by now.
The deadliest pandemic in modern history was the Spanish flu, which killed more than 30 million people between 1918 and 1920.
The researchers calculated that the probability of a pandemic of similar magnitude ranged from 0.3% to 1.9% per year, which means it's statistically likely that a similar pandemic could occur within the next 400 years.
But the increasing rate at which new pathogens have appeared among humans in the past 50 years suggests that the risk of new disease outbreaks will increase threefold in the next few decades, the researchers added.
Based on that increased risk, they estimated that a pandemic similar in scale to COVID-19 is likely within 59 years.
The authors also calculated that a pandemic capable of eliminating all human life is statistically likely within the next 12,000 years, but they didn't include that finding in the study.
But despite estimating that a pandemic on the scale of COVID-19 could occur within 59 years and one on the scale of the Spanish flu could occur within a few hundred years, they could still emerge at any time, the researchers noted.
"When a 100-year flood occurs today, one may erroneously presume that one can afford to wait another 100 years before experiencing another such event," said study co-author Gabriel Katul, a professor of hydrology and micrometeorology at Duke.
"This impression is false. One can get another 100-year flood the next year," Katul warned in the release.
Population growth, environmental destruction, changes in food systems and more frequent contact between people and disease-carrying animals may be among the factors driving more frequent pandemics, Pan suggested.
The study "points to the importance of early response to disease outbreaks and building capacity for pandemic surveillance at the local and global scales, as well as for setting a research agenda for understanding why large outbreaks are becoming more common," Pan said.
The findings are published in the Aug. 31 issue of Proceedings of the National Academy of Sciences.
The Columbia Mailman School of Public Health has more on pandemics.
SOURCE: Duke University, news release, Aug. 23, 2021