A new analysis of COVID-19 cases in the United States reveals that while older people are at high risk of becoming seriously ill, the disease can hit younger adults hard, too.

Early data from China examining the country’s first 44,000 cases had suggested that most severe COVID-19 cases and deaths happen in adults aged 60 or older and those with underlying conditions. But the first snapshot of U.S. cases, released by the Centers for Disease Control and Prevention, shows that 1 in 5 people landing in the hospital are 20 to 44 years old.

The CDC analysis, released March 18, covers 2,449 reported cases from February 12 to March 16. Among 508 patients who required hospitalization, 20 percent were 20 to 44 years old. And of 121 people who were admitted to an intensive care unit, 12 percent were in that age group.

Severe cases More than half of ICU admissions and deaths out of 2,449 reported U.S. cases of COVID-19 from February 12 to March 16 occurred in those 65 or older. But younger adults also experienced severe cases of the disease, a new analysis by the Centers for Disease Control and Prevention finds. Among hospitalized adults, 1 in 5 were 20 to 44 years old, as were 12 percent of those admitted to the ICU. Adults 45 to 64 years old made up 35 percent of hospitalized patients and 36 percent of ICU patients. Severe outcomes of U.S. COVID-19 cases by age C. Chang C. Chang Source: CDC

France and Italy are also reporting cases of younger adults falling seriously ill with the coronavirus.

Consistent with other studies, the CDC found that patients 65 and older still fared worst, making up 45 percent of hospitalizations, 53 percent of ICU admissions and 80 percent of deaths. And patients younger than 20 still appear to have milder symptoms. Few children or teens required hospitalization, and none died, the analysis found.

But not all the cases included enough information to track their care, and it’s unclear whether any of the younger adults had underlying health conditions — a risk factor for developing severe disease. That could inflate the apparent risk to younger adults. More widespread testing and tracking is needed to better pinpoint who is at risk and guide what measures communities adopt to protect vulnerable groups (SN: 3/6/20; SN: 3/13/20).

The new numbers should be a wake-up call for younger people, says Aubree Gordon, an epidemiologist at the University of Michigan in Ann Arbor. “I don’t think it has really hit home for [them] how serious this situation is,” she says. “Even if they don’t think this is going to personally impact them, they need to realize they’re contributing to overall transmission and putting a lot of people at risk,” she says.