Over the past week California’s case count has exploded, surpassing 200,000 known infections, and forcing Mr. Newsom to roll back the state’s reopening in some counties. On Monday, he said the number of people hospitalized in California had risen 43 percent over the past two weeks.

Los Angeles County, which has been averaging more than 2,000 new cases each day, surpassed 100,000 total cases on Monday, with the virus actively infecting one in every 140 people, according to local health officials. More than 2,800 cases were announced in the county on Monday, the most of any day during the pandemic…

“To some extent I think our luck may have run out,” said Dr. Bob Wachter, a professor and chair of the department of medicine at the University of California, San Francisco. “This is faster and worse than I expected. You have to have a ton of respect for this thing. It is nasty and it just lurks and waits to stomp on you if you let your guard down for a second.”…

Younger people appear to account for the large surge in new cases, as they have in many other states. Latinos, who make up a large swath of the state’s essential work force, have also recently seen consistently high case counts.