Despite 103 years of advances, the Covid-19 pandemic has killed more Americans than the 1918 flu pandemic

They included not ditching safety precautions too early; not getting a false sense of security among those young and healthy; and not relying on unproven treatments.

But Kissler said those lessons were not heeded by many.

“A lot of the mistakes that we definitely fell into in 1918, we hoped we wouldn’t fall into in 2020,” Kissler said. “We did.”

Here’s a look at some of the key differences and similarities between the 1918 pandemic flu and Covid-19:

What’s different between the two pandemics

Population: The US population is now triple what it was in 1918. So while the Covid-19 death toll may be higher, the 1918 flu pandemic apparently killed a higher proportion of Americans, Kissler said.

Now, Covid-19 vaccines are available — but millions of eligible Americans have not been vaccinated.

The rapid spread of misinformation: Kissler said he believes the biggest disadvantage now compared to the 1918 pandemic actually involves a major technological advance.

“The internet can be a double-edged sword,” he said. “It provides us with the opportunity to receive the CDC and the World Health Organization (updates) and to share information much more quickly. But that also means we can spread misinformation quickly as well.”

What’s similar between the two pandemics

Young people aren’t invincible: Just because a person is young and healthy doesn’t mean they can’t be hit hard by a pandemic virus.

About two-thirds of the deaths from the 1918 pandemic were among people ages 18 to 50, said John Barry, author of the 2004 book “The Great Influenza: The Story of the Deadliest Pandemic in History.”

It might not be surprising that the pandemic flu spread rapidly among young adults in 1918. That was the final year of World War I, and many young soldiers were close together in barracks.

Personal responsibility matters: No matter how good the science and public health advice are, “those things are only as good as the behavioral response,” Kissler said.

During the 1918 flu pandemic, when cases had dropped in San Francisco, “the city fathers said, ‘Let’s open up the city. Let’s have a great big parade downtown. We’ll all take off our masks together,'” epidemiologist Dr. Larry Brilliant said.

“Two months later, because of that event, the great influenza came back again roaring.”

On the other side of the United States, Philadelphia suffered a similar fate.

Even though 600 sailors from the Philadelphia Navy Yard had the virus in September 1918, the city didn’t cancel a parade scheduled for September 28, 1918.

“Quickly, Philadelphia became the city with the highest influenza death toll in the US,” Penn research states.

It’s possible the viruses can spread long after the pandemic: The World Health Organization defines a pandemic as the “worldwide spread” of a new disease.

Kissler said he believes SARS-CoV-2, the virus that causes Covid-19, might also stick around for years — even if the “pandemic” is over.

“We’ll get new variants,” including some that might cause reinfection, Kissler predicted. But eventually, “I do think those variants will be closely enough related, probably, to the things we’ve already been vaccinated against or the the things we’ve already been exposed to that it won’t cause the same sort of severe disease.”

He stressed the best way to gain protection and help this pandemic sputter out is to get vaccinated — not wait for exposure to the virus, which could lead to long Covid, hospitalization or death.

“Essentially, what the vaccine does is it gives you your first and second exposure for free” — without the dangers of Covid-19, Kissler said.

“That’s extremely helpful, and that goes a long way to reducing mortality.”