The coronavirus may be best known for the brutal toll it has taken on older adults, but a new study of hospital patients challenges the notion that young people are impervious, the New York Times reported.

The research letter from Harvard found that among 3,222 young adults hospitalized with Covid-19, 88 died — about 2.7 percent. One in five required intensive care, and one in 10 needed a ventilator to assist with breathing.

Among those who survived, 99 patients, or 3 percent, could not be sent home from the hospital and were transferred to facilities for ongoing care or rehabilitation.

The study “establishes that Covid-19 is a life-threatening disease in people of all ages,” wrote Dr. Mitchell Katz, a deputy editor at JAMA Internal Medicine, in an accompanying editorial.

“Social distancing, facial coverings and other approaches to prevent transmission are as important in young adults as in older people,” it said.

Nearly 60 percent of younger patients hospitalized with Covid-19 were men, and a similar percentage were Black or Hispanic. Men were more likely to need a ventilator than women, and more likely to die. Extreme obesity and hypertension were also linked to a greater risk of mechanical ventilation or death.

The study, which was peer reviewed and published in JAMA Internal Medicine on Wednesday, looked at young adults discharged from more than 400 hospitals in the United States between April 1 and June 30. Over all, just over one-third were obese, and one quarter extremely so. Roughly one in five had diabetes, and about one in seven had hypertension.

The senior author of the research letter, Dr. Scott D. Solomon, a professor of medicine at Harvard, emphasized that despite the rise in coronavirus cases among young people, the proportion who become so sick that they require hospitalization remains low.

At the same time, he said, some will become seriously ill, and Black and Hispanic people are overrepresented among them.

“We talk a lot about how young people can transmit the disease to others who are more vulnerable, but we want to make the point that some young people — it’s not a huge number compared to those getting infected — but a finite number are going to have serious consequences of this disease,” Dr. Solomon said.

Those with chronic health problems are at greater risk, but some with no apparent vulnerabilities also become acutely ill, he said.

“There are factors that we don’t understand that put people at risk with this disease,” Dr. Solomon said. “They may be genetic, they may be environmental, they may be the other viruses we’ve been exposed to in our lives. There is a randomness there.”

And researchers know very little about the long-term consequences for the young adults who recover. “What are the effects they are going to have weeks, months, even years down the line?” Dr. Solomon asked.

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