The number of daily cases has more than doubled since June 24, when the country registered 37,014 cases after a lull in the outbreak had kept the previous record, 36,738, standing for two months. Daily virus fatalities had decreased slightly until last week, when they began rising again.
Four states — Idaho, Nevada, Oregon and Texas — set single-day case records on Thursday. And three states set single-day death records on Thursday — Florida, South Carolina and Texas — with Florida and Texas alone combining for more than 300.
Seven others reached death records this week: Alabama, Arizona, Hawaii, Idaho, Montana, Oregon and Utah. Many of the states that reopened early are the ones seeing the biggest increases, while New York, the country’s hardest-hit city, has seen a 64 percent drop since June 1.
Public health experts have pointed to a few factors that help explain why the death count was initially flat. Treatment has improved and young people, who are less likely to die from Covid-19, make up a larger share of new cases.
Additionally, more widespread testing means cases are caught sooner, on average. That means that the lag between diagnosis and death would be longer than in March, when tests were in critically short supply.
In Kentucky, where the daily case average reached its highest point earlier this week, Gov. Andy Beshear warned that the grim circumstances in Arizona, Florida and Texas could soon materialize there.
“We are seeing state after state not just facing escalating cases, but facing devastation,” said Mr. Beshear, whose state reported a record number of children under age 5 testing positive. He added: “When you put up record numbers of cases, while our hospitals are working really hard, we will see more death.”