The U.S. is officially in a flu epidemic, federal health officials say. They’re preparing to deploy troops and ventilators if necessary

U.S. flu hospitalizations are higher now than they’ve been at this point in every other flu season since 2010-2011, officials with the U.S. Centers for Disease Control and Prevention said on a press call.

The country is seeing a resurgence of non-COVID respiratory illnesses like flu, RSV, rhinovirus, and enterovirus, with background levels of COVID, according to Dr. José Romero, director of the National Center for Immunization and Respiratory Diseases.

Federal officials are monitoring hospital capacity throughout the U.S. and are “standing by to deploy additional personnel and supplies as needed,” Dawn O’Connell, assistant secretary of the Department of Health and Human Services’ Administration for Strategic Preparedness and Response, said on the call.

If a state or jurisdiction exceeds its ability to care for patients, a team from the National Disaster Medical System may be deployed, she said, adding that response might also include personnel from the Department of Defense and the Federal Emergency Management Agency, or FEMA.

If extra supplies like ventilators or personal protective equipment are needed, they’re available upon request from the Strategic National Stockpile, she added. No states had requested this level of support as of Friday.

Flu causing more severe illness in the young, elderly

Federal health officials on Friday painted a picture of some respiratory illnesses like flu surging in some areas of the country, with other areas seeing peaks of RSV, or respiratory syncytial virus infection. Cases of COVID and flu-like illnesses are occurring all areas, they said.

RSV is a common virus that hospitalizes thousands of infants and young children each year, though it can also pose a risk to the elderly. Symptoms can range from mild cold-like ailments like sneezing, sore throat, fever, and stuffy nose to pneumonia, which can prove fatal. Patients can quickly take a turn for the worst.

In the Southeast U.S., nearly 20% of flu tests sent to a lab are returning positive—most of them for influenza A, which appears to be more severe in children and the elderly. In the Mid-Atlantic and Midwest regions, an early flu season is also causing severe illness in those age groups, according to Romero.

The second influenza-related pediatric death of the season was recently reported, he added.

But flu isn’t the country’s only problem when it comes to respiratory illnesses, nor is COVID. Eight out of 10 regions of the country are seeing levels of RSV “significantly higher than those seen at the same time in previous years.” And levels of “influenza-like” illness, defined as a fever with cold-like symptoms or sore throat, are also high for the time of year, Romero added.

An alert to health care providers throughout the U.S. will soon be issued, detailing best practices regarding testing and treatment for, and prevention of, the variety of respiratory illnesses being seen en masse so early this season, he said.

He advised parents of children who have trouble breathing, who appear to be blue, who are experiencing chest or muscle pain, who are dehydrated (no urine for eight hours is one sign), and/or who are not alert or interactive when awake to seek immediate medical attention.

O’Connell encouraged all Americans to cover their coughs. And she encouraged those at high risk for illness—like infants and young children, those 65 and older, pregnant individuals, and those with certain chronic health conditions—to stay away from people who are sick and wash their hands frequently, or use alcohol-based hand sanitizer.

“People may choose to wear a well-fitting mask as an added precaution,” she added. She also plugged antivirals like Tamiflu for flu and Paxlovid for COVID, though she emphasized that they must be taken shortly after symptom onset if they’re going to blunt the impact of an infection.

California’s Orange County is overwhelmed—and it’s not alone

Earlier this week California’s Orange County declared a health emergency due to an overwhelming surge in respiratory illness that’s pushing pediatric hospitals to their limits.

Sky-high numbers of young patients are seeking emergency-room care in area children’s hospitals for RSV, the flu, flu-like illnesses, and, to a lesser extent, COVID, the OC Health Care Agency said Monday. The emergency declaration allows the county to receive help from the state and federal governments, and to seek aid from nearby counties.

Children’s Hospital of Orange County is seeing upwards of 400 children in its emergency department daily—a record high—and is using all available space to meet demands. It has activated a command center within the hospital to manage the high patient load, a spokesperson told Fortune in a Tuesday statement.

Southern California is far from alone, with pediatric hospitals all across North America experiencing similar struggles—and some even considering outdoor tents to house patients and calling in the National Guard for help.

The vast majority—around 75% —of U.S. children’s hospital beds are currently full, according to NBC News. To the north, Canada is seeing similar issues, with some pediatric hospitals canceling surgeries, according to media reports. Children’s Hospital of Eastern Ontario, a pediatric hospital in Ottawa, was at 130% capacity for intensive care beds and 134% capacity for inpatient beds, respectively, last week, a Canadian TV outlet reported.

Fortune has repeatedly reached out to HHS over the past week and a half, inquiring as to the number of pediatric hospital beds occupied in the U.S., but has not received a response. But anecdotally, the figure has a ring of truth, Dr. Anita Patel, a critical care doctor at Children’s National hospital in Washington, D.C., told Fortune on Tuesday.

Patel is in contact with other East Coast pediatric hospitals, “and almost every single major one” is nearly full, she said.

Children’s National has been operating close to capacity for over a month. It’s formed an additional team of high-level ICU doctors to care for children who need ICU admission, but who must stay in the emergency room until a bed opens up, according to Patel.

The surge in pediatric patients was initially fueled by the common cold, but RSV quickly surpassed it. While levels of RSV have since plateaued, “the flu is really on a rapid rise in our region,” she said, adding that her hospital hasn’t recently seen a significant number of patients with COVID or other coronaviruses that can cause respiratory illness.

“I can honestly say that, unfortunately, with both RSV and the flu, we have had kids that needed to be intubated or have breathing tubes to help get through viral illness,” she said.

“I’ve been a practicing ICU doctor for a decade now, and I think I can safely say this is one of the worst surges I’ve ever seen.”

Doctors and public health officials have been keeping a close eye on the U.S. flu season this fall out of concern that the virus will strike early and hit children particularly hard, as it did in Australia this spring. While hospitalizations and deaths were nothing unusual there, cases of flu peaked earlier and higher. And children and teens, who usually fare well with the flu, bore the brunt. The majority of reported flu cases were among young people ages 0–14, according to an Oct. 9 report from the Australian government.