ST. LOUIS, Mo. (KTVI) – The masks are coming off and winter-like respiratory viruses seem to be coming out of lockdown at the same time.

“A number of our ER visits include patients with common respiratory viruses that we only see during winter months,” said Dr. Kurt Sobush, a pulmonologist at SSM Health Cardinal Glennon Children’s Hospital in St. Louis.

Cardinal Glennon is seeing a 20% increase in winter-like viruses, including RSV in children up to age 2.

According to the Centers for Disease Control and Prevention, RSV (respiratory syncytial virus) is a common respiratory virus that typically causes mild, cold-like symptoms that can become more severe, especially in infants and older adults.

“It’s a virus that can escalate beyond just the common cold to something that would include a faster kind of breathing,” Sobush said. “It can increase fever, it can cause at least some difficulties with respiratory distress, where children can have an increased cough that doesn’t seem to quit.”

RSV germs typically spread by coughing and sneezing. Doctors say the reason RSV cases are increasing may be related to less mask-wearing and social distancing.

“I think a lot of people blow off at least certain sniffles — things here and there — at least in the summer. That maybe it’s just allergies or maybe it’s just something else altogether,” Sobush said. “But we are seeing at least this uptick in some of the respiratory viruses that we’ve known to be serious in the past. I think it’s just something that we want parents to be cautious about.”

Last week, the CDC issued a health advisory to notify health care professionals and caregivers about increased RSV activity across parts of the southern U.S. The agency urged RSV testing for people showing signs of acute respiratory illness who test negative for SARS-CoV-2, the virus that causes COVID-19.

RSV infections in the U.S. occur mainly during the fall and winter cold and flu season. In April 2020, RSV activity quickly decreased, likely due to coronavirus-prevention measures. Compared with previous years, RSV activity stayed relatively low from May 2020 to March 2021, the CDC noted. However, since late March, the CDC has noticed an increase in reported RSV cases.

Sobush anticipates some parents will send their children to school with masks this fall regardless of whether or not their schools require them.

“I think there’s going to be certain situations where children will still be coming to school with masks being worn and I think that’s here to stay a little bit, especially when they are having viral symptoms, whereas they would otherwise go to school with just a little bit of nose sniffles,” he said.

And just as it was before the pandemic, doctors say good hand washing for children remains important to slow or stop the spread of viruses.