(CNN) — Nearly 20,000 people in the United States were hospitalized with influenza last week, nearly double the number of admissions the week before, according to data updated Friday by the US Centers for Disease Control and Prevention (CDC). , for its acronym in English).

The CDC estimates that there have been at least 8.7 million people sick, 78,000 hospitalizations and 4,500 deaths from influenza this season.

In a letter to the nation’s governors sent Friday, the US Secretary of Health and Human Services, Xavier Becerra, points out that influenza and other respiratory viruses are “increasing pressure” on the country’s health systems .

In a letter obtained exclusively by CNN, Becerra wrote that the Biden administration “stands ready to continue to assist you with resources, supplies, and personnel.”

Last month, children’s health leaders called for a formal emergency declaration from the federal government to support hospitals and communities amid an “alarming rise in pediatric respiratory illnesses, including respiratory syncytial virus (RSV) and influenza, along with the ongoing children’s mental health emergency.

Respiratory syncytial virus (RSV) threatens children in the US. 4:36

The Biden administration has not declared an RSV or influenza public emergency, but Becerra’s letter outlines ways the COVID-19 public health emergency declaration can be applied to more broadly address the challenges brought on by a confluence of covid-19 and other respiratory and seasonal diseases.

“The Administration has exercised regulatory flexibilities to help healthcare providers continue to respond to COVID-19. These flexibilities, while critical to addressing the covid-19 pandemic, can also help address many of the challenges you face during the spread of non-COVID-19-related illnesses, including RSV and influenza,” says the letter. “They continue to be available to you and healthcare providers as they all provide care in response to the flu, RSV, covid-19 and other illnesses.”

For example, if a hospital is short-staffed, it could use a waiver that would allow increased capacity or patient transfers, even if patients need treatment for something other than covid-19, such as influenza or RSV.

The letter also highlights the funding available, including $400 million from CDC to prepare for and respond to public health threats each year, including influenza and other respiratory diseases such as RSV, along with data, analysis, and other resources from planning prepared by the federal government. It also notes that the federal government is monitoring the supply chain of critical drugs and devices and that federal health officials for the past month have been engaging with the nation’s governors through a meeting hosted by the National Governors Association.

“As your federal partner, we stand ready to evaluate any request for federal medical assistance and support, including requests for medical personnel and equipment, working closely with you and local jurisdictions to determine the needs and availability of appropriate resources.” Becerra wrote.

Influenza has been highest in the South, with hot spots stretching from El Paso to southwestern Virginia. All but six states are experiencing “high” or “very high” respiratory virus levels, and seasonal influenza activity remains “high and continuing to increase,” according to the CDC.

There have been nearly 17 flu hospitalizations per 100,000 people this season, rates typically seen in December or January. The cumulative hospitalization rate hasn’t been this high at this point in the season in more than a decade.

The latest monitoring data probably does not capture the full effects of holiday gatherings, as they only capture up to November 26, two days after Thanksgiving.

While the flu continues to rise, RSV has shown signs of slowing across the country, but test positivity rates remain higher than they have been in years, and cumulative hospitalization rates are about 10 times higher. higher than typical for this point in the season. Less than two months later, this season’s RSV hospitalization rate is already approaching the total RSV hospitalization rate for the entire 2018-19 season.

There is no vaccine for RSV, but health officials have urged people to get their flu shots and covid-19 booster shots before winter. With the holiday season and flu season underway, Dr. Anthony Fauci warned this week of the possibility of an emergency situation.

“When you have very little leeway from intensive care beds, when almost all intensive care beds are occupied, it is bad for children who have RSV and need intensive care. But it also takes up all the beds, and kids who have a host of other illnesses that require intensive care or ICUs, they don’t have the bed for that,” Fauci, director of the National Institute of Allergy and Infectious Diseases, said on “Face the Nation” on CBS on Sunday. “So if it gets to that situation, it’s approaching an emergency.”