COVID-19 is surging among America's youth. Doctors worry children of color face the greatest risk.

On Thursday, Ana Amira Rivera celebrated her first birthday. But earlier this month, her mom worried her baby girl wouldn’t make it.

Ava woke up one night in early August with a fever and seizures. Estefani Lopez rushed her to the emergency room, where her daughter stopped breathing, going limp in her arms. The otherwise healthy baby was diagnosed with COVID-19.

Doctors stabilized Ava and said she needed to get immediately to the ICUbut there were no beds. All pediatric ICUs in Houston were full. She was airlifted to the closest, 150 miles away in Temple, Texas.

"My heart sank to the floor,” said Lopez, 22. “I felt like I was going to lose my daughter before she even turns 1."

While severe illness, hospitalization and death from COVID-19 are still considered rare among children, those of color like Ava have been disproportionally sickened. And with cases climbing as the contagious delta variant rips through the unvaccinated, health experts fear what's to come.

Earlier this month, baby Ava Amira Rivera was hospitalized with severe illness from COVID-19. Pediatric ICU beds in Houston hospitals were full, and she had to be flown to a hospital 150 miles away.

The COVID-19 vaccines aren't yet available for children younger than 12, and with schools reopening more kids are getting infected. In Florida, where new cases lead the nation and Gov. Ron DeSantis has banned school districts from mandating masks, children make up roughly 10% of cases since the start of the pandemic, according to the American Academy of Pediatrics.

COVID vaccines and children:Pfizer's vaccine is FDA-approved for adults, but it's still a 'no-no' to vaccinate kids under 12

Nationwide,children accounted for more than a fifth of COVID-19 cases reported the week ending Aug. 19, the AAP reported. In the past two weeks alone, cases among children increased 7%. Doctors expect it will only get worse.

Science is still catching up with the pediatric surge, but experts worry about children of color, who disproportionately suffer from lack of access to health care, obesity and other chronic conditionsand COVID-19, too. The disparity is likely to continue. 

“I don’t see a reason why it wouldn’t,” said Dr. Sean O’Leary, a Denver, Colorado pediatric infectious diseases specialist and vice chair of the AAP Committee on Infectious Diseases. "Those kids are at higher risk for hospitalization in general."

People of color have disproportionately higher hospitalization rates among every age group – including kids under 18, the Centers for Disease Control and Prevention says.

Since the start of the pandemic through last month, children who are Black, Hispanic, American Indian and Alaska Native were all hospitalized about three times more often than white children and teens, according to the CDC.

To date, more than a third (34.8%) of the more than 450 children and teens who have died of COVID-19 were Hispanic, according to CDC numbers. Almost a quarter (23.3%) were Black, even though Black children only make up 13% of U.S. children. Hispanic kids make up about 25%. White children, who make up half of U.S. kids, accounted for less than a third of those who died.

And more than half – 63% – of reported children with the rare but serious multisystem inflammatory syndrome associated with COVID-19 were Hispanic or Black, CDC data shows.

Dr. Cindy Darnell Bowens, who oversees the pediatric ICU at Children’s Medical Center in Dallas, said the medical community is working hard to figure out which children are in most danger of getting seriously sick.

Ava Amira Rivera turned 1 Aug. 26. Earlier this month, she suffered severe illness from COVID-19. ICU beds in local hospitals were full, and she had to flown to a hospital 150 miles away.

More:The delta variant of COVID-19 is more contagious for children. Is it making them sicker, too?

"We do worry about the children who don't have access to receive treatments, to receive routine follow-up visits, to receive preventative care, for obesity, for asthma, for diabetes," she said. "I do worry that those children will be more susceptible to becoming severely ill from this illness and other illnesses."

Across the medical center, more than three dozen children were hospitalized with COVID-19 Wednesday, a spokeswoman said. On her ICU rounds that day, Darnell Bowens, also a University of Texas Southwestern critical care professor, said she saw many children with those comorbidities. 

“We are seeing a significant number of obese teenagers present with respiratory failure from COVID,” said Darnell Bowens. “There does seem to be some connection with severity of illness and obesity, but it's hard to, at this point, say how causal that connection is.” 

'Need to be on higher alert':Babies and toddlers more likely than teens to transmit coronavirus, study says

Pediatric pulmonologist and professor of pediatrics Dr. Deepa Rastogi specializes in asthma in children of color and obesity-related asthma at Children's National Hospital in Washington, D.C. While scientists are still learning about the new disease, she said it appears children with poorly controlled asthma and with obesity might be at greater risk from COVID-19.

Rastogi said it's possible to infer that the same racial disparities seen in adults might continue among children.

"For the sake of the children I take care of, I hope that is not the case," she said.

Dr. Judith Flores, a New York City pediatrician and fellow of the American Academy of Pediatrics, said it's up to adultsto get vaccinatedto ensure children are surrounded by a "good community of protection."

COVID-19 vaccines for children under 12: When are they coming?

"The most important thing for them is to make sure that as many people around them  are vaccinated," said Flores, who provides COVID-19-related education for Latino communities. "If you look at it nationally, risk is determined by your locality, risk is determined by your community, and the rate of infection and rate in vaccination."

Experts like Darnell Bowens are racing against time to both keep children alive and healthy, and to learn more about COVID-19.

Earlier this month, baby Ava Amira Rivera was hospitalized with severe illness from COVID-19. Pediatric ICU beds in Houston hospitals were full, and she had to be flown to a hospital 150 miles away.

“I feel like we all need roller skates," she said. "With the admissions and discharges and our ongoing surgeries and resuscitating kids, we escalate to a 15 out of 10. We've been operating in overdrive for weeks now.” 

Lopez wishes people would adhere to mask mandates and get the shots. She said it's the least adults can do to protect other people, especially children and babies who can't effectively wear masks. 

"You might be able to fight it off, but my daughter almost died from it," she said.“Our children, they have their whole lives ahead of them."

Reach Nada Hassanein at nhassanein@usatoday.com or on Twitter @nhassanein_.