Dr. Osterholm says a typical flu season kills 36,000 people every year, and the very young and very old are most at risk "because they are the ones that are most vulnerable to infectious diseases."
Not exactly the case with bird flu, he says. If the bird flu is anything like the 1918 pandemic, some of the highest death rates could actually be "those between the ages of 20 and 40."
"In the months of September and October of 1918, 7 percent of the residents of Boston between 20 and 40 years of age died," he says.
How could individuals in the prime of their health be so susceptible to a disease? "It turns out that this virus multiplies very quickly in your body," Dr. Osterholm explains. "The people who have the healthiest immune systems are the ones that succumb to the virus because the immune system goes into overdrive."
The demographic least likely to survive the 1918 pandemic were pregnant women, Dr. Osterholm says. "Fifty-five percent of all pregnant women died from having this flu virus. There is no more precarious time in a healthy person's immune system, than [when they are] pregnant. Part of you says, 'Get rid of that [baby]. It's not all me.' And part of you says, 'This is the most precious cargo I'll ever carry. Protect it.'" This confusion makes bird flu extremely dangerous for pregnant women.