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More and more children are testing positive for COVID-19, and some doctors are not only reporting an uptick in cases but more severe illness for kids who contract the virus. 

According to the American Academy of Pediatrics, 93,824 child COVID-19 cases were reported between July 29 and August 5, with children representing 15% of the weekly reported cases in the U.S. Since July 22, the total number of child COVID-19 cases has jumped 4%. As of August 5, nearly 4.3 million children in the U.S. have tested positive for COVID-19 since the start of the pandemic. 

And while severe illness due to COVID-19 is uncommon among children, “there is an urgent need to collect more data on longer-term impacts of the pandemic on children, including ways the virus may harm the long-term physical health of infected children, as well as its emotional and mental health effects,” the academy says.

Some doctors in Seattle have reported an increase of children with serious illness from COVID-19, urgent care nurse practitioner Justin Gill told CBSN last week. Gill said kids are not as susceptible to serious illness as adults, but with more cases come more hospitalizations. 

“With Delta variant, we are seeing some younger people, even vaccinated and unvaccinated, but the vast majority of cases who get hospitalized tend to be unvaccinated individuals,” Gill said. Kids under 12 cannot yet receive COVID-19 vaccines, which are still undergoing testing in younger age groups. 

“Many of the people admitted here at Seattle Children’s, as mentioned by multiple articles here, are unvaccinated people over the age of 12 and unvaccinated under the age of 12,” Gill said. He added that vaccine approval for children under 12, which could come this fall, will be a big step in reducing those numbers.

Health experts believe the Delta variant is behind the uptick in cases. Dr. John McGuire, who works in the Pediatric Intensive Care Unit at Seattle Children’s, told CBS Seattle affiliate KOMO he hopes to get through this latest wave of the pandemic “as quickly as possible.”

McGuire said a vast majority of child COVID-19 cases are in kids who are too young to get the shot — or whose families are unvaccinated.  

“That’s worrisome,” he said. “We had hoped that with increased vaccine in the general population, we would see fewer cases.”

“One way to protect [kids], because they’re not yet eligible, is to have the people that they’re around be vaccinated,” he added.

Gill said masks are also important to reduce the spread of COVID-19, including for vaccinated people who may be exposed to high loads of the virus. 

“Mask use, specifically in schools where you have a large number of unvaccinated children potentially, is a common sense step to help us get over the pandemic,” he said. 

Seattle isn’t the only U.S. city seeing a surge in children’s cases. CBS News correspondent David Begnaud reported Sunday night that Children’s Hospital New Orleans currently has 18 children hospitalized with COVID-19, including six in the ICU and three who were on ventilators.

Begnaud visited Children’s Hospital New Orleans on July 29, when the hospital reported 20 children hospitalized with COVID-19. “A lot of these kids are very sick with respiratory symptoms. Literally starved for oxygen,” Dr. Mark Kline told Begnaud.

Jacquez Lee, a 17-year-old high school football player, was in the emergency room experiencing difficulty breathing, headaches and coughing. 

“If he wouldn’t have gotten the first dose of the vaccination, his sickness would’ve been way worse than what it is now,” his mother, Fatina Watkins, said. 

Louisiana has one of the nation’s lowest vaccination rates, and over just two weeks 1% of the state’s entire population has caught the virus, CBS News’ Mark Strassmann reported on “Face the Nation.”

“We have more children sick with COVID-19 than at any other time during the pandemic,” Governor John Bel Edwards said.

Texas and Florida now make up about one-third of COVID-19 cases in the U.S., and governors of both states oppose universal mask rules as schools open. The American Academy of Pediatrics has recommended that all children over the age of 2 wear masks when they go back to school.

Among adolescents and teens who are old enough to get vaccinated, the Centers for Disease Control and Prevention says about 51% of 16-17-year-olds and 40% of 12-15-year-olds have gotten at least one dose. About 7.7 million are fully vaccinated.

The CDC says that while children are generally at lower risk for serious illness from COVID-19 than adults, those with preexisting conditions may face more severe symptoms. And even some previously healthy kids are ending up hospitalized.

study published in April that observed a cohort of more than 20,000 pediatric COVID-19 patients found that 2,430 — 11.7% — were hospitalized, and about 31% of those hospitalized experienced severe illness.

Several studies also show that some children may experience lingering symptoms, or “long COVID.”

A study out of Gemelli University in Rome followed 129 children ages 18 or under who were diagnosed with COVID-19, and found that about a third of them had one or two lingering symptoms four months or more after infection, and a quarter had three or more symptoms, including insomnia, fatigue, muscle pain and persistent cold-like complaints, according to the study, published in Acta Paediatrica journal.