About 18 years ago, while delivering a talk at a CDC conference, Gregory Poland punked 2,000 of his fellow scientists. Ten minutes into his lecture, a member of the audience, under Poland's instruction, raced up to the podium with a slip of paper. Poland skimmed the note and looked up, stony-faced. "Colleagues, I am unsure of what to say," he said. "We have just been notified of a virus that's been detected in the U.S. that will take somewhere between 10,000 and 15,000 lives this year." The room erupted in a horrified, cinematic gasp. Poland paused, then leaned into the mic. "The name of the virus," he declared, "is influenza." Call it funny, call it mean, but at least call it true. Poland, a physician and vaccinologist at Mayo Clinic, had done little more than recast two facts his colleagues already knew: Flu is highly contagious and highly dangerous, a staggering burden on public health; and for years and years and years, Americans, eve...