This time, a majority of patients counted as covid cases in some hospitals were initially admitted for other reasons, their covid infections discovered incidentally. And hospital staffs are stretched more than ever, with nearly 1 in 4 medical centers reporting this week they have a “critical” staffing shortage, the highest proportion of the pandemic.

In Los Angeles, where the fast-spreading omicron variant reigns, roughly two-thirds of covid patients in the county’s public hospitals were initially admitted for other causes, officials said Wednesday.

But at CoxHealth in Springfield, Mo., where officials say the older delta variant remains a ferocious threat, the coronavirus remains the immediate cause for 81 percent of covid hospitalizations.

“We are planning on a pretty scary scenario: volumes increasing and being short-staffed,” said Steve Edwards, the hospital’s CEO, warning that omicron could soon arrive and sicken his workers.