With novel coronavirus infections setting a single-day national record Wednesday, health experts are taking little solace from one of the few bright spots in the current resurgence: Deaths are not rising in lockstep with caseloads.

But that may be just a matter of time.

“Deaths always lag considerably behind cases,” Dr. Anthony Fauci, the nation’s top infectious-disease specialist, told Congress at a hearing Tuesday. In the weeks to come, he and others said, the death toll is likely to rise commensurately.

Which means Arizona, Texas and Florida, states that reopened early and now are experiencing runaway infection rates, are likely to be burying more dead in July.

“As long as there is a fair amount of testing going on, if there is an uptick in COVID-19 infections, then we are likely to see that in the confirmed case data before we see it in the death data,” said Nicholas Reich, associate professor of biostatistics at the University of Massachusetts at Amherst, in an e-mail.

He predicted “rises in COVID-19 deaths over the next month in many of the states that are seeing upticks in cases, like Texas, California, Florida and others, even though the deaths have been either steady or declining in recent weeks.”

The virus has come surging back in recent days, with 38,115 U.S. infections Wednesday, according to a tally from the Washington Post. That’s more than any previous day in the pandemic, including the catastrophic days of April. This time, the increases are mainly in the South and West, while New York and New Jersey, which were nearly overwhelmed in the spring and have been slow to reopen, are seeing declining cases.

California, which shut down early and has taken a slow approach toward reopening, nevertheless reported more than 7,000 new cases Wednesday, easily surpassing its record of 5,019 set Tuesday. Oklahoma — where President Donald Trump on Saturday held an indoor campaign rally — and Florida also hit new single-day highs Wednesday.

Those three states, along with Nevada and North Carolina, reached new peaks in their seven-day rolling averages, considered a more reliable indicator of the virus’s impact. Arizona set a record with 2,270 hospitalizations.

Coronavirus hospitalizations have tripled in Houston since Memorial Day, Houston Methodist Hospital chief executive Marc Boom said. Texas reported 5,551 new cases, the most in a single day, along with 4,389 hospitalizations, up almost 300 from Tuesday’s record high.

The state’s seven-day rolling average of new cases has increased 70% since last Tuesday, setting a record for the 14th consecutive day.

Overall, nearly 2.36 million people have been infected in the United States and more than 120,000 have died — by far the largest numbers for any country in the world.

Despite the numbers, Vice President Mike Pence urged Republican senators during a closed-door lunch to focus on “encouraging signs.” Lawmakers have begun to express alarm about rising infection rates in states such as Florida, Arizona and Texas, which are likely to be critical in the outcome of the presidential race and control of the Senate.

Senators said Pence pointed to positive indicators, including the lagging mortality rate. That is partly because there is more testing, and younger and healthier people now account for larger shares of those getting tested, Pence contended.

Officials tracking the startling comeback of COVID-19, the disease caused by the virus, are somewhat buoyed by lessons learned and progress in the health care system since the virus stormed ashore outside Seattle in late February and later inundated New York City.

Some said the greater availability of tests is responsible for turning up more cases. The results of those tests are revealing a larger number of younger people with the virus than there were in the early days of the outbreak.

When the pandemic first gripped the United States, it was nearly impossible for anyone without severe symptoms to secure a test. Younger people, who generally suffer milder cases and are more likely to be asymptomatic, may have been underrepresented as a result, said Jennifer Nuzzo, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health’s Center for Health Security.

Now they are accounting for some of the rise in the overall caseload and a greater proportion of hospitalizations in places like Arizona. There may be fewer deaths among the younger group, but those individuals are likely to infect more older people, she said.

With states reopening, “you have the young folks out and about. They’re spreading it,” she said. “It may take time to find its way to older, vulnerable people, who are more likely to die.”

Tom Frieden, former director of the CDC, said older people now have a better understanding of how vulnerable they are. The medical system also has taken steps to better protect people older than 65, including those living in nursing homes and other care facilities. The virus is no longer racing through those places and killing people by the dozens, as it did early in the pandemic.

CDC statistics show how thoroughly COVID-19 attacks the elderly. From Feb. 1 to June 13, COVID-19 was involved in just 2,630 deaths among people 44 or younger. But the disease was fatal to 83,426 people 65 or older.

Even if the death toll does not rebound to previous levels, the current surge will have serious consequences, said Saskia Popescu, an infectious-disease epidemiologist who teaches at the University of Arizona.

For some people who do not become critically ill, the virus can cause severe, and sometimes long-lasting, problems, she said.

“Illness is a really significant outcome too,” Popescu said. “Deaths are obviously worst case; we don’t want people to die. But I don’t want people to get sick, especially so sick they have to go the hospital. That’s hard on them, that’s hard on the health care system. Focusing only on deaths does a disservice to patients and the community.”