This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

This time of year, it’s typically playground injuries and a few broken bones that keep doctors busy inside Lurie Children’s Hospital.

But the pace is picking up for a different reason.

“This week, we’ve had about 20 cases of RSV,” said Dr. Larry Kociolek, Lurie’s Children Hospital Infectious Disease Specialist. “Only a few of those children have required the hospital, which is pretty typical, but we anticipate those numbers are going to increase further.”

Why is Respiratory Syncytial Virus, usually not expected until later in the year, arriving so soon?

“Normally, these viruses present in the wintertime and those babies get immunity and it goes away, and we don’t see it again until the next fall. However, with the stay-at-home advisories, with frequent masking, with schools being closed, all infectious illnesses in children went down,” Dr. Kociolek said. “Now, RSV is essentially catching up offseason.”

Kociolek says he’s never seen anything like it. It’s the same scenario at Advocate Children’s Hospital, where RSV counts have spiked throughout the suburban system. 

“Usually, the numbers are close to zero at this time of year, and they are higher than they have been yet in 2021,” said Dr. Shannon Staley, Pediatric Emergency Medicine at Advocate Children’s Hospital. “While RSV is spread the same way as COVID is, it’s less contagious, so a lot of that masking and social distancing was part of the reason we didn’t see much of it earlier in the year.”

Infants and children two and younger are most commonly affected by RSV. What can look like a common cold at first can escalate — symptoms range from cough, runny nose and congestion to serious breathing problems – a sign a baby’s small airways have filled with mucus. 

“With RSV, you can get mucus in your airways,” Dr. Kociolek said. “When those airways are really small, like in babies under two, it can lead to wheezing and difficulty breathing and sometimes respiratory failure that requires an intensive care unit admission. 

“Sometimes the breathing can be so rapid that it makes it very difficult for kids to eat and drink.”

In those cases, call your doctor or go to the ER immediately. Milder symptoms should peak by day four. 

“If the symptoms have been going on for four or five days and the child is relatively well, we’re confident the child will not need the hospital. If it’s day one or two, particularly if the baby is really young, it’s very possible that child is going to worsen and going to escalate over the next few days,” Dr. Kociolek said.

There may be an upside to the late surge.

“Some of those babies if they would have been exposed at three or four months in the wintertime, now that they are bigger their lungs are better developed, their airways are bigger,” Dr. Kociolek said. “They might have a more mild presentation of RSV now than they would have in the wintertime.”

“If a lot of children happen to be exposed and get some immunity to RSV, it could make our winter season mild, but we still have a lot to learn, and I will not be surprised either way, and predictions can be complicated during COVID,” Dr. Kociolek added.

Researchers are working on an RSV vaccine – and MRNA technology used for the COVID vaccine could help lead the way. Philadephia and New York saw an RSV surge in March. Chicago’s uptick surfacing over the last month.