In N.Y.C.’s Coronavirus Surge, a Frightening Echo of the 1918 Flu

The 1918 influenza pandemic is the deadliest in modern history, claiming an estimated 50 million lives worldwide, including 675,000 in the United States.

By some measures, the toll of the Covid-19 surge in New York City this spring resembled that of the 1918 flu pandemic. In March and April, the overall death rate was just 30 percent lower than during the height of the pandemic in the city, despite modern medical advances, according to an analysis published on Thursday in JAMA Network Open.

Many people liken Covid-19 to seasonal influenza while regarding the 1918 flu pandemic as a time of incomparable devastation, said Dr. Jeremy Faust, an emergency medicine physician at Brigham and Women’s Hospital in Boston and lead author of the analysis.

“But in reality, what 1918 looked like is basically this,” he said, except with dead bodies in refrigerated trucks rather than piled in the streets.

“I want people to realize the magnitude of what we just saw this spring, what we’re seeing now again, is truly historic,” Dr. Faust added.

Historians who have studied the 1918 pandemic agreed. “It’s especially important to the pandemic deniers who are saying, ‘Oh, this isn’t any worse than, say, the 1968 flu pandemic,’” said Dr. Howard Markel, a historian at the University of Michigan.

“This is a pretty deadly pandemic. And it’s only getting worse — that’s the scary part.”

Amid a pandemic, it can be difficult to determine an exact cause of death, even with sophisticated diagnostic tools. So Dr. Faust and his colleagues compared data for “all-cause mortality” — deaths from any cause — in New York City during two pandemic periods.

Nearly 33,500 people died in New York City between March 11 and May 11 of this year, according to the city’s Department of Health and Mental Hygiene. With a total population of nearly 8.3 million, this amounts to an incident rate of 202.08 deaths per 100,000 person-months — a standard way of denoting deaths over time.

The overall death rate in those 61 days was more than four times the rate in the corresponding periods in 2017 through 2019.

The researchers then looked at deaths in October and November of 1918, the peak of the city’s flu outbreak. They found detailed mortality statistics collected by the Census Bureau, which was then a relatively new agency, and archived by the Centers for Disease Control and Prevention.

Dr. Faust identified 31,589 deaths among 5.5 million city residents, for an incident rate of 287.17 deaths per 100,000 person-months. This number was nearly three times higher than the city’s death rate in the previous three years. In all, the death rate in the city last spring was about 70 percent of that seen in 1918.

When the epidemic hit in 1918, the spike in deaths was not as shocking to the city as it was in 2020. At the time, the increase in deaths was less than three times higher than the previous year’s toll, the researchers noted, whereas 2020’s rise was more than four times higher than 2019’s figure.

Simply put, life was riskier a hundred years ago.

“It was a less healthy and a less safe world,” Dr. Faust said. In one sense, he added, “we’re worse off today than in 1918,” because we started from a much safer, technologically advanced place. The impact of an epidemic should have been dramatically lower today, not slightly lower.

Indeed, people today are conditioned by the “medical industrial complex” to think that all diseases can be conquered, said Nancy Tomes, a historian of American health care at Stony Brook University.

That may be why many Americans, particularly those who believe the pandemic is overblown, are so angered to find that a virus has upended their lives, she added.

“In 1918, people were very familiar with infectious diseases and dying from them,” Dr. Tomes said. “There was not this whole kind of expectation that we have today that this shouldn’t be happening.”

Given the enormous leaps in medicine over the past century, the similarity in death rates today and in 1918 is particularly disconcerting, she and other experts said.

In 1918, a vaccine against the flu mistakenly targeted Haemophilus influenzae, a bacterium, instead of the flu virus. Penicillin — which would have vanquished the bacterial pneumonia that killed many people with the 1918 flu — would not be discovered for another decade. Intravenous fluids to hydrate the severely ill came into use even later.

Without these tools, the hospitals of 1918 were little more than places to rest.

“There was no such thing as an intensive care unit, there was no ventilator, there was nothing,” said Dr. Eric Topol, director of the Scripps Research Translational Institute in San Diego.

“I mean, they basically had masks and distancing. We have so much more, and yet the mortality is roughly comparable.”

Other experts noted that Dr. Faust and his colleagues compared the worst months of Covid-19 with a period in 1918 that did not precisely coincide with the city’s worst bout with influenza.

The New York City Department of Health’s data for 1918 would have enabled the researchers to include deaths from September 15, the start of the peak — “a better time period,” said J. Alexander Navarro, a medical historian at the University of Michigan.

Still, he added, that was a “nitpicky” detail that would not would have changed the message of the analysis.

The parallels between the two pandemics reinforce concerns that the fall and winter this year could bring a second wave worse than the first, as happened in 1918.

The similarities also raise uncomfortable questions about the how much deadlier the coronavirus may be than the 1918 flu virus.

If you could pluck the two viruses out of time and compare them, Dr. Faust said, it’s not clear which would be inherently more deadly: “It could be that this thing is much closer to 1918,” he said, referring to the coronavirus. “Or it could be worse.”