As the influenza pandemic swept across the United States in 1918 and 1919, masks took a role in political and cultural wars More than a century ago, as the 1918 influenza pandemic raged in the United States, masks of gauze and cheesecloth became the facial front lines in the battle against the virus. But as they have now, the masks also stoked political division.  In 1918 and 1919, as bars, saloons, restaurants, theaters and schools were closed, masks became a scapegoat, a symbol of government overreach, inspiring protests, petitions and defiant bare-face gatherings. All the while, thousands of Americans were dying in a deadly pandemic. The first infections were identified in March, at an Army base in Kansas, where 100 soldiers were infected. Within a week, the number of flu cases grew fivefold, and soon the disease was taking hold across the country. By the end of October, there were more than 60,000 cases statewide, with 7,000 of them in San Francisco. It soon became known as the “masked city.”

Spanish flu is a category 5 influenza pandemic that began to spread in the United States, appeared in West Africa and France, then spread to most of the world. This disease is caused by Influenza Virus Type A subtype H1N1. Most victims of this flu are adults and young people.

The terrible scale of the 1918 influenza pandemic known as the "Spanish flu" is very difficult to understand. This virus infects 500 million people worldwide and kills around 20 million to 50 million victims.