How the Coronavirus Compares With 100 Years of Deadly Events

A wave of homicides devastated Chicago in 2016. But it caused only a small increase in overall mortality in the city.

A bad flu season in New York City raised all deaths to 1.05 times higher than during a normal winter.

Neither event nears the extraordinary wave of death during the coronavirus pandemic. We compared deaths in the worst months of the outbreak to past years, a measure often used to assess a disaster’s severity.

Even in Oslo, which has avoided a major outbreak, about 15 percent more people died than normal — rivaling the worst month of the AIDS epidemic in New York City.

The outbreak’s death toll in Miami rivals that of one of America’s worst recent flu seasons in Seattle.

Hurricane Maria killed thousands of people in Puerto Rico in 2017. Many died after widespread power outages overwhelmed hospitals. The increase in death was similar to the outbreak’s toll in Brazil’s two largest cities.

Demographers call these “mortality shocks” — sudden spikes in the total number of people dying not seen in the weeks before an event, and not likely to last once it is over. They’re often found during natural disasters, severe flu seasons, famines or wars.

Nearly 3,000 people in New York City died in a single day on Sept. 11, 2001. It was one of the largest mortality shocks in recent American history. Sixty percent more people died that September than normal.

On a relative scale, deaths increased more in Denver in March.

Death during the outbreak is often less visible than death from a terrorist attack or a natural disaster. Many people have died quietly, in nursing homes or at home. And some die without being tested and are excluded from official death counts.

These estimates include all deaths, offering a more complete accounting of the outbreak’s toll than official tallies. They include people who died directly from the coronavirus and those who died from other causes as hospitals have been stretched and people avoid seeking medical care.

The 1957 flu pandemic, also known as the Asian flu, killed at least one million people worldwide. In Santiago, Chile, one of the worst-hit cities, mortality doubled. That increase was only a little higher than the one during the coronavirus in Detroit.

Any disaster past this line — that is, one in which normal deaths double — should be declared an emergency, according to guidelines from the United Nations High Commissioner for Refugees.

Sweden kept schools and businesses open as most of Europe closed them and ordered citizens to stay home. The country has seen an extraordinary increase in deaths, especially in Stockholm. More than twice the usual number of people died there in April.

While national figures can broadly show the situation in each country, they can also obscure acute crises in densely populated cities, like Boston, where the virus spread rapidly before officials told people to stay home.

“If you’re looking at the total impact of the pandemic across an entire country, it may not seem like much is going on,” said Robert Anderson, chief of the mortality statistics branch at the C.D.C.’s National Center for Health Statistics. “If you really want to know what’s happening, you need to look at states, cities and local areas.”

Major cities with large outbreaks, like Paris, have rates of excess death far higher than the rest of their countries.

Few places have seen excess deaths of this scale — more than three times normal.

Now we see Boston’s toll during the 1918 flu, also known as the Spanish flu, the worst pandemic of the 20th century. It killed at least 50 million people worldwide, with about 675,000 deaths in the United States.

As the toll has eased in New York and in European capitals, cities across Latin America have begun to see astonishing increases in deaths. Deaths spiked in Lima in April despite a strict lockdown. More than 11,000 people died in May, about 8,000 more people than in previous years. That surpasses the worst month of the 1918 flu in New York City.

These figures reflect deaths only through May. In many cities in Latin America, Asia, Africa and the Middle East, the outbreak is still getting worse.

“Oh my goodness,” Dr. Anthony S. Fauci, the United States’ top infectious disease expert, said on Tuesday. “Where is it going to end? We’re still at the beginning of it.”

Few places ever see excess deaths of this scale outside of famine or war.

The death toll in Ecuador — one of the worst in the world — was far higher than the official number of Covid-19 deaths reported by the government. In Guayas, a coastal province that includes the city of Guayaquil, deaths spiked by more than five times.

The coronavirus is unlikely to kill as many people as the Spanish flu did, but in the modern history of natural disasters, it will have few rivals.