Millions Would Die in Modern Flu Pandemic

Key Point

Researchers estimate that a severe, modern-day influenza pandemic may cause between 51 million and 81 million deaths worldwide, with underdeveloped countries being the hardest hit.

CAMBRIDGE, MASSACHUSETTS—The influenza pandemic of 1918-1920—one of the deadliest disease events in human his­tory—killed an estimated 40 million to 50 million persons. But what would happen today if an influenza strain of similar severity emerged?

Christopher J. L. Murray, MD, and colleagues from the Harvard School of Public Health sought to answer this question by reanalyzing data from 1918 and applying global mortality patterns from that time to 2004 population data.¹ The results, published in the Lancet, showed that a severe influenza pandemic today would cause an estimated 51 million to 81 million deaths worldwide—a mortality rate 114% higher than the norm. It is likely that 96% of these deaths would occur in poor countries.

The investigators calculated epidemic and pandemic influenza mortality rates in 1915-
1923 in 27 countries around the world. They found a huge variation in excess mortality rates due to influenza, ranging from 0.2% of the population of Denmark to 4.4% of the population of India. In the United States, rates ranged from 0.25% in Wisconsin to 1.0% in Colorado. “Normally, about 1% of the world’s population dies in a year,” Dr. Murray noted.

Income per capita accounted for almost half of the variance in pandemic mortality; however, the researchers acknowledged that other unique community attributes that influenced mortality rates are still unknown.

These findings are all the more compelling as concerns of a new pandemic—specifically, avian influenza caused by the H5N1 strain—continue to mount. Results from the new study clearly imply that international attention should focus on providing protection for poor countries.

“In some high-income regions, vaccination strategies might help, depending on how quickly they can be deployed and how many deaths will occur during the first wave of the pandemic,” Dr. Murray said. Another strategy that may help in developed countries is use of antibiotics for secondary bacterial pneumonia.

“The public health message here is don’t let the perfect be the enemy of the good,” Dr. Murray warned. “We need to think of strategies that might work in the poorest settings.”

—Adriene Marshall

Reference
1. Murray CJL, Lopez AD, Chin B, et al. Estimation of potential global pandemic influenza mortality on the basis of vital registry data from the 1918-20 pandemic: a quantitative analysis. Lancet. 2006;368:2211-2218.

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