NEW YORK — In September, an 8-month-old baby came to Dr. Juanita Mora’s office in Chicago with an infection the doctor didn’t expect to see for another two months: RSV.

Like her peers across the country, the allergist and immunologist treated toddlers for this cold virus long before the season began.

“We’re seeing RSV infections spread across the country,” Moreau said.

The US Centers for Disease Control and Prevention states that almost all children contract RSV at some point before they are 2 years old. In most adults who have caught it, the disease is mild; it can be dangerous for those who are elderly or have chronic heart or lung disease or a weakened immune system. But RSV can be especially challenging for babies and children.

Moreau, a volunteer medical representative for the American Lung Association, says it’s important for parents, caregivers and daycare workers to know what to watch out for with RSV, which stands for respiratory syncytial virus. This is how they will find out whether a sick child can be treated at home, or whether he needs to be treated in a hospital.

“The emergency room is completely overwhelmed with all these sick kids, so we want parents to know that they can go to their pediatrician and get tested for RSV, flu and even Covid-19,” Mora said.

Here’s what else parents need to know amid a surge in respiratory illnesses.

What to watch out for

In many people, RSV causes a mild illness that can be managed at home.

On average, the infection lasts from five days to several weeks and often resolves on its own, the CDC says. Sometimes the cough can last up to four weeks, pediatricians say.

Symptoms can be similar to the common cold: runny nose, loss of appetite, cough, sneezing, fever and wheezing. Young children may only appear irritable or lethargic and have trouble breathing.

Not every baby will have all the possible symptoms of RSV.

“Fever does occur with RSV infections, especially in young infants,” said Dr. Priya Soni, assistant professor of pediatric infectious diseases at Cedars Sinai Medical Center.

She said parents should watch for any changes in behavior, including taking longer to eat or not being interested in food at all. The child may also develop a severe cough and some wheezing.

It’s also important to watch for signs that your child is having trouble breathing or breathing through their ribs or abdomen — “symptoms that can be consistent with many other viruses that we’re seeing resurgence,” Sonny added.

Because it’s not easy for parents to tell the difference between respiratory illnesses like, say, RSV and the flu, it’s a good idea to take a sick child to a pediatrician who can run tests to determine the cause.

“You might have to take the baby in for a check-up sooner rather than later,” Sonny said.

When it comes to RSV, parents should be especially careful if their children are premature, newborns, children with weakened immune systems or neuromuscular disorders, and children under age 2 with chronic lung and heart disease, the CDC says.

“Parents should be very alert to any changes, such as in their activity and appetite, and then pay close attention to any signs of respiratory distress,” Sonny said.

Treatment of RSV

Testing is important because treatments for illnesses such as the flu and Covid-19 can vary.

There is no antiviral or specific treatment for RSV like the flu, and there is no vaccine. But if your child is sick, there is something you can do to help.

Fever and pain can be relieved with non-aspirin pain relievers such as acetaminophen or ibuprofen. Also make sure your child is drinking enough fluids.

“RSV can cause severe dehydration in children, especially if they’re not eating or drinking, especially when we’re talking about babies,” Mora said. “Once they stop eating or their urine volume decreases, they don’t have as many wet diapers, which is a sign that they may need to go to the pediatrician or the emergency room.”

Talk to your pediatrician before giving your child any over-the-counter cold medicines, which can sometimes contain ingredients that are not suitable for children.

When to go to the hospital

Your pediatrician will check your baby’s respiratory rate — how fast he’s breathing — and his oxygen levels. If your child is very sick or at high risk of serious illness, the doctor may want to send him to the hospital.

“RSV can be very dangerous for some infants and young children, especially those younger than 2 years old,” Sonny said.

Mora said that labored breathing is a sign that a child has a problem with this virus. RSV can develop into more serious illnesses, such as bronchiolitis or pneumonia, which can lead to respiratory failure.

If you see your baby’s chest move up and down with breathing, if the cough keeps him awake, or if it gets worse, “this may be a sign that he needs to see a pediatrician or take him to the emergency room, because then they may need supplemental oxygen or they may need nebulization treatment.”

CNN medical analyst Dr. Leana Wen says that these breathing difficulties — including head bobbing, a runny nose or grunting — are one of the two main signs of trouble with any respiratory infection. Another is dehydration. “This is especially true for babies with stuffy noses. They may not feed.”

Most of the care provided by hospital staff will focus on breathing assistance.

“We are providing supportive measures for RSV and these children with oxygen, IV fluids and respiratory therapy, including suctioning,” Sonny said.

A thin tube may need to be inserted into their lungs to remove the mucus. The child may receive supplemental oxygen through a mask or through a tube attached to the nose. Some children may require the use of an oxygen tent. Those who experience great difficulty may need a ventilator.

Some babies may also need to be fed through a tube.

How to prevent RSV

Doctors say the best way to prevent RSV infection is to teach children to cough and sneeze into a tissue or elbow, not into their hands. Also, try to keep surfaces you touch often clean.

Moreau says if a caregiver or older sibling is sick, they should wear a mask around other people and wash their hands often.

And most of all, if someone is sick – child or adult – they should stay at home to avoid spreading the disease.

There is a treatment with monoclonal antibodies for children who are at the highest risk of severe disease. It is not available to everyone, but it can protect those who are most vulnerable. It comes as a shot that a child can get every month during a typical RSV season. Talk to your doctor to see if your child qualifies.