More kids were hospitalized with Covid-19 this month than any other time this past year -- proving how seriously the Delta variant can hit any age group.
Between August 20 and 26, an average of 330 children were admitted to hospitals every day with Covid-19, according to the US Centers for Disease Control and Prevention.
That's the highest rate of new Covid-19 hospitalizations among children in more than a year -- a record that was broken several times in August, according to CDC data.
"This virus that we're dealing with now is a game changer," said Dr. Mark Kline, physician-in-chief of Children's Hospital New Orleans.
"It's just so easily transmitted from person-to-person." As of August 9, he said, "half of the children that we've admitted have been under the age of 2."
Doctors say it's crucial to protect children against the Delta variant -- not just for the sake of their health and to keep in-person learning, but also to help prevent more aggressive variants from setting the entire country back.
204,000 new pediatric cases in one week
Since the last school year, a more contagious variant -- Alpha -- has been replaced by an even more contagious variant -- Delta -- as the dominant strain of coronavirus in the US.
In just two months, Delta jumped from 3% to more than 93% of sequenced coronavirus samples in the US, the CDC said.
Now, Covid-19 cases among children have "increased exponentially," the American Academy of Pediatrics said Tuesday.
During the week ending August 26, about more than 200,000 new childhood Covid-19 cases were reported, the AAP said.
That's a "five-fold increase the past month, rising from about 38,000 cases the week ending July 22nd to nearly 204,000 the past week."
Among kids getting hospitalized with Covid-19, many were previously healthy.
Almost half -- 46.4% -- of children hospitalized with Covid-19 between March 2020 and June 2021 had no known underlying condition, according to CDC data from almost 100 US counties.
MIS-C and long Covid can leave lasting impacts
Long-term Covid-19 complications can be significant for children -- even for some who initially had mild or no symptoms, the American Academy of Pediatrics said.
All pediatric patients who tested positive should have at least one follow-up exam with a pediatrician, the AAP said.
Pediatricians should watch out for residual or long-term Covid-19 problems such as respiratory symptoms, which can last three months or more; heart issues, including a type of heart inflammation known as myocarditis; cognitive problems such as "brain fog"; headache; fatigue and mental health issues, the AAP said.
Children who had moderate or severe Covid-19 may be at greater risk for subsequent heart disease, the pediatrician group said.
In some cases, children who start with mild or even no symptoms from Covid-19 end up hospitalized weeks or months later with a condition called MIS-C -- multisystem inflammatory syndrome in children.
MIS-C is "a rare but serious condition associated with COVID-19 in which different body parts become inflamed, including the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal organs," the CDC says.
It happens when "the virus induces your body to make an immune response against your own blood vessels" -- which can cause inflammation of the blood vessels, said pediatrician Dr. Paul Offit, director of the Vaccine Education Center at the Children's Hospital in Philadelphia.
Often, children with MIS-C don't start off very sick with Covid-19.
"Usually children are picked up incidentally as having (coronavirus). Someone in the family was infected; a friend was infected, so they got a PCR test. And they're found to be positive. ... Then they're fine," Offit said.
"Then a month goes by, and they develop a high fever. And evidence of lung, liver, kidney or heart damage. That's when they come to our hospital."
Protecting kids from Covid-19 is critical to keep them in schools
With the highly contagious Delta variant, the CDC recommends students from kindergarten through grade 12, along with teachers and visitors, wear masks in school.
The American Academy of Pediatrics recommends masks in schools for everyone older than 2.
"Our children deserve to have full-time, in person, safe learning with prevention measures in place. And that includes masking for everyone in schools," Walensky said.Some students are returning to schools for the first time in a year. But long-awaited classroom learning can be quickly derailed by an infection or outbreak.
In Mississippi and Florida, thousands of students just starting their school year have already had to quarantine.
And it doesn't take much for Covid-19 to shut down a school again. Even one case can have a ripple effect on students, faculty and staff.
"We need adults to run schools, and if my adults are sick or needing to quarantine, I don't have adults present to provide the education," said Carlee Simon, superintendent of Alachua County Public Schools in Florida.
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"When we have families that don't want to have masks on their child, what they're doing is not only (increasing the) chance they will have to be quarantined," Simon said.
If a student gets infected, "they will also have other students who did have masks on who would also need to be quarantined."
"Everybody wants to move forward. Nobody wants to have masks forever," Simon said. But "we would like to be able to be safe and have instructional time with our students."
In addition to masks in schools, the CDC recommends layering other strategies such as improved ventilation, physical distancing and testing on a screening basis.