By educating people on how influenza could spread, public health officials hoped to help people avoid it. This image was created by one of the nation's most famous cartoonists, Clifford T. Berryman. The 1918 flu pandemic (Spanish flu) was an influenza pandemic. It was an unusually severe and deadly pandemic that spread across the world. Most victims were healthy young adults, in contrast to most influenza outbreaks, which predominantly affect juvenile, elderly, or weakened patients. The pandemic lasted from June 1918 to December 1920. Between 50 and 100 million died, making it one of the deadliest natural disasters in human history.