The influenza pandemic of 1918–19, also called the Spanish flu, lasted between one and two years. The pandemic occurred in three waves, though not simultaneously around the globe.

At the time, there were no effective drugs or vaccines to treat this killer flu strain. Citizens were ordered to wear masks, schools, theaters and businesses were shuttered and bodies piled up in makeshift morgues before the virus ended its deadly global march. READ MORE: See all pandemic coverage here.

The 1918 Pandemic Improves Patient Care Russia, France, Germany and the U.K., among others, put centralized healthcare systems in place, while the United States adopted employer-based insurance plans. Both systems expanded access to healthcare for the general population in the years following the pandemic.

After infecting an estimated 500 million people worldwide in 1918 and 1919 (a third of the global population), the H1N1 strain that caused the Spanish flu receded into the background and stuck around as the regular seasonal flu.

When influenza appeared in the United States in 1918, Americans responded to the incursion of disease with measures used since Antiquity, such as quarantines and social distancing. Yet even in this trying context, the historical record reveals that many Americans responded courageously during the crisis.

In summary, our data supports the idea that the 1918 Spanish flu influenza virus was derived from a swine virus that itself might be a descendent of a distinct avian H1N1 virus. What we can say for sure is that the 1918 H1N1 virus is not related to one of the known avian influenza strains, except the clade 1 viruses.

Lasting from February 1918 to April 1920, it infected 500 million people – about a third of the world’s population at the time – in four successive waves.

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. Then, as now, medical authorities urged the wearing of masks to help slow the spread of disease. And then, as now, some people resisted.

The virus hit in three waves, with the second during the fall of 1918 specifically spelling devastation on US soil. Cities across the country shut down churches and schools, required residents to wear masks, and erected makeshift hospitals to help fight the disease.

The zoonotic and spatial origins of the influenza virus associated with the “Spanish flu” pandemic of 1918 have been debated for decades. Outbreaks of respiratory disease in US swine occurred concurrently with disease in humans, raising the possibility that the 1918 virus originated in pigs.

Presented data support the hypothesis that the 1918 pandemic influenza virus was able to infect and replicate in swine, causing a respiratory disease, and that the virus was likely introduced into the pig population during the 1918 pandemic, resulting in the current lineage of the classical H1N1 swine influenza viruses …

Harris believes that the rapid spread of Spanish flu in the fall of 1918 was at least partially to blame on public health officials unwilling to impose quarantines during wartime.

A temporary hospital in Camp Funston, Kansas, during the 1918–19 influenza pandemic. Influenza is caused by a virus that is transmitted from person to person through airborne respiratory secretions.

The most effective efforts had simultaneously closed schools, churches, and theaters, and banned public gatherings. This would allow time for vaccine development (though a flu vaccine was not used until the 1940s) and lessened the strain on health care systems.