(NEXSTAR) — Hospitals throughout the country have been reporting an uptick in children being hospitalized for respiratory syncytial virus, commonly known as RSV. Amid a flu season expected to be serious and with COVID-19 still infecting thousands each week, some are warning that we could be entering a challenging few months.

“We have already seen above what we expect for October any given year in terms of RSV locally and around the country,” Diego Hijano, an infectious disease specialist at St. Jude Children’s Research Hospital, told The Hill. Over the last week, nearly 7,000 RSV tests came back positive, according to figures from the Centers for Disease Control and Prevention, well above the roughly 30 reported during the same time last year.

Dr. Julie Holland, vice president of Pediatric Primary Care for Chicagoland Children’s Health Alliance tells Nexstar’s WGN there are concerns patients could get all three viruses at once.

So how can you tell these viruses apart?

First, it’s important to note the most serious symptom: difficulty breathing. If your child is struggling to breathe, regardless of why, seek immediate medical attention. Signs of this may include being able to see your child’s ribs while they are breathing, their lips becoming pale or blue, or the area below your child’s Adam’s apple collapsing.

WHO IS MOST AT RISK?

Anyone can get these viruses, but infants are among the most vulnerable, as are older adults and those with weakened immune systems.

In the case of RSV, a young child’s smaller airways make them more susceptible.

“Their airways are smaller, so inflammation and extra mucus make it harder for them to breathe,” Dr. Joe Childs with East Tennessee Children’s Hospital explained to Nexstar’s WATE. “Especially in the first few months of life, it can be very nasty.”

Their younger immune systems can also leave them more vulnerable to the flu. Holland says that when it comes to the flu and RSV, “the younger you are, the sicker you get.”

While young children can get COVID, many that do catch it have been found to have no symptoms, according to Harvard Medical School. If they do have symptoms, they tend to be milder. Children are, however, at risk of experiencing a severe complication known as multisystem inflammatory syndrome in children, or MIS-C, after being exposed to or having the virus that causes COVID. MIS-C can lead to problems with the heart, lungs, kidneys, brain, skin eyes, or gastrointestinal organs, according to the CDC.

WHAT ARE THE SYMPTOMS?

All three viruses have similar symptoms among young children, Michael Meyer, medical director of the Pediatric Intensive Care Unit for Children’s Wisconsin wrote in a Monday blog post.

“These include a stuffy or runny nose, a cough, headache, and a low fever,” Meyer writes. “Their appetite may also be lower, and for nursing babies that can mean less wet diapers.”

These symptoms are similar to those listed for COVID by the CDC and the flu by John Hopkins Medicine. The flu does include additional symptoms, such as high fever, body aches, nausea, vomiting, and diarrhea.

Among younger children, RSV, an upper respiratory infection, can also cause wheezing and respiratory distress, Holland said. But she added that you can’t tell what virus someone is experiencing just by observing their symptoms. Instead, you’ll need a diagnosis from a medical professional.

HOW ARE THE VIRUSES DIAGNOSED?

A COVID diagnosis requires a nasal swab test, either with a PCR test or an antigen test. Testing for RSV, though usually not necessary according to the American Lung Association, is commonly done using a mouth swab or blood test. If your doctor suspects your child has the flu, testing may include nasal or throat swabs.

HOW TO KEEP YOUR CHILD SAFE

While telling the viruses apart can be difficult, protections for your child are the same for all of them.

Meyer encourages washing your hands often and ensuring anyone coming in contact with your child has washed their hands. If your child or anyone else in your home isn’t feeling well, they should remain at home. Those who aren’t feeling well also shouldn’t visit your home. He further recommends keeping surfaces clean since viruses can live on hard surfaces.

There is no vaccine for RSV, but vaccines are available for COVID and the flu.

The flu vaccine is recommended for most children that are 6 months and older, according to John Hopkins.

Two COVID vaccines — Pfizer-BioNTech and Moderna — have been approved for children as young as 6 months old. A third vaccine, Novavax, has been approved for children as young as 12 years old.

During RSV season, an injection of an antibody-based medicine is sometimes prescribed to protect premature infants and other very vulnerable babies. Infants of mothers who had RSV while pregnant may have some immunity as well.

Regardless of whether your child has RSV, the flu, or COVID, if you’re worried your child is having a severe breathing problem, “do not hesitate” to go to an emergency department or call 911, said Dr. Russell Migita of Seattle Children’s Hospital.

For less severe medical problems, Migita said, call your regular health care provider for advice, use telehealth or go to urgent care.

The Associated Press contributed to this report.