The flu usually kills the very young, the elderly and the sick. This made the virus unusual in 1918, or so the story goes: It killed healthy young people as readily as those who were debilitated or had chronic conditions.
Doctors of the time reported that, in the prime of their lives, good health and youth were not preserved: the virus was blinding, killing at least 50 million people, or between 1.3 and 3 percent of the world’s population. In contrast, Covid killed 0.09 percent of the population.
But A Paper Published Monday in Proceedings of the National Academy of Sciences. Using evidence from the skeletons of those who died in the 1918 outbreak, researchers reported that people with chronic diseases or malnutrition, regardless of their age, were twice as likely to die as those without such conditions.
The 1918 virus killed the young, but it was no exception to the observation that infectious diseases kill the weak and sick most easily.
Sharon DeVitte, an anthropologist at the University of Colorado, Boulder and author of the paper, said the finding had a clear message: “We should never expect any accidental cause of death to be blind.”
Analysis of the skeletons was conducted by University of Michigan historian J. Alex Navarro makes “a fascinating article and a very interesting approach to studying this issue.”
The paper’s lead author, Amanda Whistler, an anthropologist at McMaster University in Ontario, said she was intrigued by claims that the 1918 virus instantly killed young and healthy people with pre-existing conditions. In those days, there were no antibiotics or vaccines against childhood diseases, and tuberculosis was rampant among young people.
There was a mystery as to who died of the flu, however, which fueled speculation about poor health. The mortality curve for influenza is unusual, W-shaped. Normally, mortality curves are U-shaped, indicating that children and the elderly with immature immune systems have higher mortality rates.
W arose in 1918 because the death rate increased among people between the ages of about 20 and 40, as well as among children and the elderly. This suggests that young people are particularly vulnerable, regardless of whether they are healthy or chronically ill, according to many contemporary reports. Fever is an equal opportunity killer.
In a report, the noted pathologist Colonel Victor Vaughan described a scene at Fort Devens, Massachusetts. He wrote that he saw “hundreds of young men in their country’s uniforms, in groups of 10 or more, coming into the wards”. By the next morning, he said, “the dead bodies were stacked like ropes in the ward.”
The influenza epidemic, he wrote, “made a most formidable toll, sparing neither soldier nor citizen, and flaunting its red flag in the face of science.”
Dr. Whistler and Dr. DeVitte have done it Similar research In the Black Death, he found a way to test the hypothesis about youth. If they have chronic illnesses like tuberculosis or cancer, or other stressors like nutritional deficiencies, their jawbones develop small bumps.
Assessing weakness by looking for those bumps is a “very systematic” method, said Peter Balis, a fever specialist at the Icahn School of Medicine at Mount Sinai.
The researchers used skeletons at the Cleveland Museum of Natural History. Its collection of 3,000 remains, housed in large drawers in a large room, includes each person’s name, age and date of death.
When examining the jawbones of 81 people aged 18 to 80 who died from the epidemic, Dr Whistler said the remains were treated with “great respect”. Twenty-six of them were between the ages of 20 and 40.
For comparison, the researchers examined the bones of 288 people who died before the pandemic.
The results were clear: Those whose bones were weakest when they got infected — whether they were young or old — were by far, the most vulnerable. Many healthy people were also killed, but the chronically ill were more likely to die.
That makes sense, said Dr. Arnold Monto, an epidemiologist and professor at the University of Michigan’s School of Public Health. But while the new study made an “interesting observation,” he said, the skeletons were not a random sample of the population, so it was difficult to be specific about the risk from frailty.
“We’re not used to the fact that young healthy adults are going to die,” which often happened in the 1918 epidemic, Dr. Monto said.
Dr. Bales said there was a reasonable explanation for the W-shaped mortality curve of the 1918 flu. This means that people over the age of 30 or 40 were more likely to have been exposed to a similar virus, which gave them some protection. Younger adults are not exposed.