The White House will hold a coronavirus briefing on Wednesday after a six-week hiatus, as caseloads and hospitalizations climb around the country and the Biden administration signaled that it would extend its declaration of Covid-19 as a public health emergency.

The briefing — scheduled for 10:45 a.m. Eastern — will be the first formal on-camera session led by President Biden’s new coronavirus response coordinator, Dr. Ashish K. Jha.

Dr. Jha has spent much of his first month in office trying to persuade Congress to authorize billions of dollars in new emergency aid for the pandemic response, but the administration’s request is stalled on Capitol Hill. A senior administration official, speaking on condition of anonymity to preview Wednesday’s coronavirus briefing, said Dr. Jha would again call on Congress to release the funding, and would warn that the nation was seeing a “significant increase” in infections — a sign that Covid is not over.

On Monday, the administration quietly let pass a deadline for lifting the public health emergency, which has allowed the government to take steps like offering Americans free Covid-19 vaccines, tests and treatments; barring states from canceling people’s Medicaid coverage; and expanding access to telehealth appointments. It has also allowed hospitals to get paid more for treating Medicare patients who have Covid.

The public health emergency was set to expire on July 15, but the administration promised to give states and health providers 60 days’ notice before lifting it. That deadline passed Monday with no such notification. Public health experts and hospital officials praised the extension.

“We’re seeing rising cases and hospitalizations and testing positivity rates; now is not the time to end these flexibilities that allow great access to care,” said Ashley Thompson, senior vice president for policy development at the American Hospital Association. “We are not out of the woods yet.”

The Biden administration is bracing for a surge of cases that some experts say could mirror the wave in December and January, after the highly contagious Omicron variant emerged. At the peak of that surge, the nation was recording an average of more than 800,000 new infections a day, and experts believe many more cases were not reported.

The big unanswered question, experts say, is whether the rise in cases that is already well underway will be followed by a rise in hospitalizations and deaths. According to a database maintained by The New York Times, the daily average of new coronavirus infections reported in the United States has surpassed 100,000 for the first time since Feb. 20. That figure is up 61 percent from two weeks ago.

Hospitalizations are rising, but more slowly; they are up 25 percent over the past two weeks. Deaths are continuing to decline, but deaths are a lagging indicator and that trend could reverse.

“We could be entering a period where we have an increased number of cases but a substantially decreased severity of illness, so that we see fewer hospitalizations and many fewer deaths,” said Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. “But as absolutely uncomfortable and unsatisfactory as this is, we just don’t know what this virus is going to throw at us in the next 90 days.”

That poses a messaging challenge for the White House, he said: “What we need to do is not whipsaw from, ‘We’re over,’ to ‘Oh my God, how bad it could be.’ ”

In the six weeks since the last formal White House briefing, conducted on April 5 by Dr. Jha’s predecessor, Jeffrey D. Zients, mask mandates have been lifted on airplanes and other forms of public transit, and Mr. Biden has been consumed by other crises, including the war in Ukraine and, now, the racist shooting in Buffalo.

Several experts said in interviews that they were eager for the return of the briefings, which have typically included Dr. Anthony S. Fauci, Mr. Biden’s top medical adviser, and Dr. Rochelle Walensky, the director of the Centers for Disease Control and Prevention. Both will join Dr. Jha on Wednesday.

White House officials offered no explanation for the six-week break, other than to say that Dr. Jha was reconstituting the Covid response team after a string of departures when Mr. Zients left.

Dr. Jha, a former dean of the Brown University School of Public Health who was a go-to expert for media outlets before he joined the administration, has appeared frequently on television in recent weeks, as has Dr. Fauci. Dr. Walensky held her own Covid briefing at the end of April. But such appearances do not carry the same weight as formal briefings with the imprimatur of the White House.

“I think it would be important for us to get more direction from Dr. Walensky and Dr. Fauci as to what we should be doing right now,” said Dr. Janis M. Orlowski, the chief health care officer at the Association of American Medical Colleges.

Dr. Ezekiel Emanuel, an oncologist, medical ethicist and University of Pennsylvania professor who led an effort to draft a new pandemic strategy called “The Next Normal,” was more blunt in calling for the White House to improve its Covid communications strategy: “They need to step up their game.”