Killer Findings: Scientists piece together 1918-flu virus

The “Spanish” flu killed an estimated 20 million to 50 million people worldwide between 1918 and 1919. Hoping to prevent such a deadly outbreak from recurring, scientists have long strived to figure out what characteristics differentiate that strain from other, more-benign varieties. Because researchers have lacked live samples of the killer virus, however, they couldn’t answer this pivotal question.