COVID-19 didn't just affect schools, concerts and vacations - it disrupted other viruses, too.
Cases from common respiratory infections have been historically low the past few years, health experts say, as offices closed, students learned virtually, and Americans wore masks to combat the coronavirus. But with school in full swing and winter viruses returning to seasonal patterns, hospitals across the country are beginning to fill up with sick kids.
"We are continuing to see a very high number of sick children with various respiratory problems," said Dr. Stan Spinner, vice president and chief medical officer of Texas Children's Pediatrics and Texas Children's Urgent Care in Houston. "It was already pretty high before school started, but it has clearly gotten worse and faster than it typically takes."
Health experts say most hospital admissions are dominated by respiratory syncytial virus, rhinoviruses and enteroviruses, which mostly cause coldlike symptoms, including a runny nose, sneezing, coughing and a fever.
But a growing number of young children are going to the emergency room this year, as they lack immunity from prior infection, said Dr. Elizabeth Schlaudecker, clinical director of the Division of Infectious Diseases at Cincinnati Children's Hospital.
"A lot of children everywhere are getting these viruses for the first time in rapid succession," she said. "It's a strain on the health care system because some of these kids are more sick or require medical attention."
Viruses on the rise: CDC warns against enterovirus D68, AFM
The Centers for Disease Control and Prevention issued a health alert warning physicians to prepare for an increase of enterovirus D68 (EV-D68), which has been linked to a rare but serious condition called acute flaccid myelitis.
While AFM cases are still rare, the results can be devastating. It affects the nervous system, causing muscle weakness that sometimes leads to permanent paralysis. More than 90% of cases occur in young children, according to the CDC.
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The CDC said the disease has peaked in the U.S. every two years between August and November since 2014, when the agency first began AFM surveillance. Officials expected cases to rise again in 2020, but health experts say pandemic mitigations may have stunted viral transmission.
Surveillance data shows EV-D68 is back, Schlaudecker said.
"In August, we started to see a large number of (EV-D68) cases," she said. "We have seen some correlation with EV-D68 and cases of AFM so we're encouraging pediatricians and other healthcare providers to be on the lookout."
Luckily, Schlaudecker has yet to see a rise in AFM cases this year. As of Sept. 28, the CDC reported 19 confirmed cases and 48 cases under investigation.
Get your kids vaccinated against flu and COVID, experts say
Although these viruses are making a comeback, health experts are also warning parents against influenza and COVID-19.
The American Academy of Pediatrics reported children represent more than 15% of weekly cases as of Sept. 29, which may be undercounted as health experts say some parents refuse to test their symptomatic children.
Many schools follow CDC guidelines and require students stay home for at least five days after a COVID-19-positive test, Spinner said. Some parents avoid testing so their children don't have to stay home.
"If they're not running a fever or coughing their head off, (some kids) don't want to miss school and parents don't want to miss work," he said.
Winter viruses mostly cause mild disease, but health experts say parents should be aware of signs requiring medical attention like a fever lasting longer than three days, difficulty breathing, and vomiting or diarrhea. They also encourage Americans to stay up to date with their flu and COVID-19 vaccines.
"Don't wait until your child gets really sick before you seek care and get your kids their flu shot," Schlaudecker said.
Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.
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This article originally appeared on USA TODAY: Flu, COVID, RSV: Children are getting sick with winter viruses