One-quarter of us extra vulnerable to coronavirus

The coronavirus is now striking in geographic areas where more Americans are older or have underlying health problems, making them extra vulnerable to complications from COVID-19, the disease caused by the virus.

That bodes poorly for the U.S. death toll, which has now topped 4,600.

The novel coronavirus first took root on the West and East coasts, where Americans are disproportionately younger and healthier than the general population. Now cases are spiking in Florida, where Republican Gov. Ron DeSantis just last week ordered a statewide lockdown, even though 1 in 5 Florida residents are 65 years or older.

While underlying conditions aren't always present in victims of the virus, they frequently are. That's according to illustrative new data from the Centers for Disease Control and Prevention.

Nearly 4 in 5 coronavirus patients put in intensive care units had at least one underlying health condition, out of 7,160 COVID-19 cases researchers analyzed. Of the ICU patients, 32% had diabetes, 29% had cardiovascular disease, 21% had chronic lung disease and 12% had long-term kidney disease.

Within the entire group, 184 patients died. And 173 of those had an underlying condition.

"COVID-19 is a respiratory disease," my Washington Post colleagues Joel Achenbach and William Wan report. "The virus typically infects the upper respiratory tract, but it can also venture deeper into the lungs and in some patients results in pneumonialike symptoms, requiring hospitalization and sometimes intubation on a ventilator. People who smoke or have chronic lung conditions are especially vulnerable."

Thirty-eight percent of American adults have a higher risk of developing serious illness from the virus, according to an estimate by the Kaiser Family Foundation. Of that group, just over half are at elevated risk because they're at least 65. The rest have heart disease, chronic obstructive pulmonary disease (COPD), uncontrolled asthma, diabetes or a body mass index greater than 40.

The federal data is comparable to statistics states have released. Officials in Louisiana, where 14% of people have diabetes, announced that 40% of people who died of COVID-19 had that illness. Twenty-three percent had chronic kidney disease. Just 3% of those who died had no underlying condition.

The virus is now the third-leading daily cause of death for Americans, after cancer and heart disease. It hasn't even been three weeks since San Francisco became the first city to order a lockdown - and now life has dramatically changed for virtually every American, as people face staying at home for at least four more weeks, and maybe longer.

Amid all these dismal headlines, there's a spot of bright news. Washington and California - those coastal states where the coronavirus first appeared - are finding that social distancing is working.

Those states were the first to report community cases of COVID-19 and also the first in the nation to mandate residents stay at home to keep physically apart. Analyses from academics and federal and local officials indicate those moves bought those communities precious time - and also may have "flattened the curve" of infections for the long haul.