Nationally, the death toll is rising by around 600 to 700 a day, even as record numbers of new cases were diagnosed this week. That’s far below the height of the pandemic when more than 2,500 deaths were reported some days. Medical experts say it’s too soon to know for sure that deaths are still declining.

That disparity has health experts and the public asking questions: Is it because those getting sick now are younger than those who fell ill in March and April? Are we getting smarter about the use of ventilators? Are new drugs like Gilead Sciences Inc.’s remdesivir helping? Are cases milder because of warm weather?

“The uncertainty right now is as high as it has ever been since the very scary early days in mid-March,” said James Scott, a professor of data science at the University of Texas in Austin. He’s part of a University of Texas modeling team that predicts that deaths will tick up in July.

Complicating matters, there can be a weeks-long lag in many states between when someone dies and when that’s included in the daily reports. That means deaths could be on the rise days before states say they are.