The BBC's regular feature "Witness History" recently broadcast this fascinating story.
Over 50 million people died from influenza during the 1918-19 influenza pandemic. Scientists trying to understand why that particular strain of flu was so virulent, dug into Alaska's permafrost to find traces of it to study. Kate Lamble has been speaking to Dr Jeffery Taubenberger who sequenced the genome of the so-called "Spanish" flu virus.
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