Assistant Professor Jessica Ho says in general, most countries are experiencing the highest death rates from COVID-19 at the older ages and for men, as was observed in China, Italy, South Korea and the United States.
For the United States, Ho adds that the age patterns were nicely summarized by a recent CDC report: “This first preliminary description of outcomes among patients with COVID-19 in the United States indicates that fatality was highest in persons aged ≥85, ranging from 10% to 27%, followed by 3% to 11% among persons aged 65–84 years, 1% to 3% among persons aged 55-64 years, <1% among persons aged 20–54 years, and no fatalities among persons aged ≤19 years.”
Part of why deaths are so concentrated at the oldest ages is due to frailty and comorbidities, says University Professor and AARP Professor of Gerontology Eileen Crimmins. The underlying conditions put older adults at increased risk for negative health outcomes from COVID-19.
“When they talk about older people at greater risk for poor outcomes from COVID-19, it is not a small number,” Crimmins says. “The majority of people over 70 have one of the underlying conditions that is said to put them at higher risk for poor outcomes from COVID-19.”
Because COVID-19 is a respiratory illness, it is particularly serious among older adults with other respiratory or cardiovascular diseases, Ho adds.
“Some have speculated that older current and former smokers are at particularly high risk due to compromised lung function, and that historical patterns of smoking explain, for example, why Italy has been harder hit by South Korea,” she says. “A large percentage of older Italians, especially men, are former or current smokers. A relatively lower percentage of older Korean men are smokers, and this figure is especially low for Korean women. Smoking patterns also likely explain why men have higher death rates than women, since they tend to smoke/have smoked at much higher rates over their lifetimes.”
Potential explanations for the hospitalization rates for younger adults seem less clear, in part because data on other characteristics of younger adults besides their age, such as whether they are immunocompromised, is lacking, she explains.
“One possibility is that younger adults are much more mobile, go out a lot, and have been getting exposed to COVID-19 at very high rates, leading to higher rates of getting the disease and being hospitalized, but because they tend to be in much better shape physically than older adults, they are better able to recover from the disease, and their mortality rates are much lower,” Ho says.