Shots - Health Blog
1:42 pm
Tue June 26, 2012

Swine Flu May Have Killed Far More People Than Thought

Originally published on Tue June 26, 2012 1:58 pm

The swine flu pandemic that raced around the world in 2009 seems like ancient history now.

One reason it's easy to forget is that the H1N1 strain of flu virus turned out to be milder than was originally feared. Still, there's no doubt the flu killed a lot of people around the world. But how many?

The answer isn't so easy to come up with. Only a small fraction of cases were actually confirmed with lab tests, even in highly developed countries like the U.S.

But an analysis published in the journal Lancet Infectious Disease puts the worldwide death toll from swine flu at 201,200 during the pandemic. The flu also exacerbated heart trouble in some people with cardiovascular conditions, which would add another 83,300 deaths.

One official stat put the global death toll at 18,500. But that figure was based on the cases confirmed by lab data.

In this analysis, researchers from the U.S. Centers for Disease Control and Prevention and colleagues from universities and other government around the world tried to fill in the blanks for countries where reporting of flu and flu-related deaths were spotty.

Among their findings: 80 percent of the deaths related to swine flu occurred in people younger than 65, and the majority of deaths were in Southeast Asia and Africa.

Now, it's true that these estimates are, well, estimates, subject to some pretty wide error bars because of assumptions about the rates of symptomatic flu cases and their lethality in different parts of the world.

For context, the CDC says that deaths from seasonal flu in the U.S. have ranged from around 3,000 to 49,000, depending on the year.

Still, the bottom line for swine flu is pretty clear, as an accompanying editorial noted:

"[The] findings confirm that the 2009 influenza pandemic was far from the doomsday scenario of a 1918-like pandemic that could have caused millions of deaths worldwide."

One lesson, though, is that better tracking and estimates for influenza are needed.

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.