The Spanish flu isn’t gone

The Spanish flu never really went away. Known as “the mother of all pandemics,” the flu killed up to 100 million people worldwide and infected one-third of the global population in a two-year span, but by the 1920s it had lost most of its virulence. Rather than dying out, the original virus mutated into strains that are the direct ancestor of modern flu viruses. “You can still find the genetic traces of the 1918 virus in the seasonal flus that circulate today,” says researcher Jeffrey Taubenberger. He led a team of scientists who in the late 1990s obtained the Spanish flu’s genetic signature by extracting viral RNA from autopsied lung samples from American soldiers and an Alaskan woman whose body remained preserved in the permafrost. When descendants of the Spanish flu have combined with bird flu or swine flu viruses, creating a new strain, they’ve caused deadly new pandemics, including in 1957 and 1968 (1 million people worldwide died in each) and in the swine flu pandemic of 2009, which killed 300,000. “We’re still living in what I would call the ‘1918 pandemic era’ 102 years later,” says Taubenberger, “and I don’t know how long it will last.”