In general, the U.S. experience largely mimics China's, with the risk for serious disease and death from Covid-19 rising with age. But in an important qualification, an
analysis by the Centers for Disease Control and Prevention reported on Wednesday underlines a message that infectious disease experts have been emphasizing: Millennials
are not invincible. The new data show that up to one-fifth of infected people ages 20-44 have been hospitalized, including 2%-4% who required treatment in an intensive care unit.
Still, the most severe cases, and the highest rates of death, are among the elderly. Although 17% of the U.S. population is 65 or older, 31% of cases were in that age group, CDC experts concluded in the Morbidity and Mortality Weekly Report. While it is possible that the elderly have more chances to be infected than younger people, such as by living in nursing homes, that is considered unlikely, since younger adults encounter many others at work and school.
Instead, the higher case rate among older Americans strongly suggests a true underlying, biological vulnerability, probably exacerbated by preexisting illnesses which, according to data from China, sharply raise the risk of both infection and serious illness.
That likely explains why although older Americans represented 31% of the cases, they accounted for 45% of hospitalizations, 53% of ICU admissions, and 80% of deaths, the CDC reported.
In contrast, no ICU admissions or deaths were reported among people younger than 20.