New preliminary data from the Centers for Disease Control and Prevention is helping create a picture of the spectrum of illness caused by COVID-19 in the U.S.
The findings echo what's been documented in China: The risk of serious disease and death is higher in older age groups. But they aren't the only age groups at risk.
An analysis of cases in the U.S. found that 45% of hospitalizations, 53% of intensive care admissions and 80% of deaths were among people 65 and older. The highest percentage of deaths associated with COVID-19 was among people 85 and older.
However, younger adults also can be vulnerable to serious illness. Among 508 patients known to be hospitalized, 38% were younger than 55.
About 18% of them were 45 to 55 years old, and 20% were 20 to 44 years old. It's not clear from the CDC analysis whether these younger patients had underlying medical conditions or habits (such as smoking) that would make them more vulnerable.
And while children and teens can spread the coronavirus, they appear to be much less vulnerable. The CDC report found no deaths among people 19 and younger — and less than 1% of hospitalizations involved people in that age range.
When it comes to U.S. case counts, the CDC study found that of about 2,450 infected people whose ages were known, about 25% of them were 65 and older. But 29% were 20-44 years old.
It's important to underscore that these findings, published Wednesday in the CDC's Morbidity and Mortality Weekly Report, are preliminary. There are now nearly 10,000 confirmed cases in the U.S. — and as testing ramps up, there will be a much clearer picture of just how many people of all ages have been infected.
Although this study provides an early snapshot, data on ICU admissions and deaths were missing for many cases and more time is needed to determine the outcome of active cases. In addition, at the beginning of an epidemic, the health care system is identifying the sickest people — those who go to hospitals for treatment — and is likely missing people who have only mild symptoms.
As the CDC researchers concluded, it's possible that "these data might overestimate the prevalence of severe disease."
All of this underscores the need for more testing to truly understand the scope of the cases and illnesses.