The Delta variant is sending more children to the hospital. Are they sicker, too?

Pilar Villarraga had spent much of the summer counting down the days until her daughter Sophia’s birthday. In early August, Sophia would turn 12 — and become officially eligible for a COVID-19 vaccine. “I didn’t want her to start school without the vaccine,” said Villarraga, who lives in Doral, Florida.

And then, in late July, just two weeks before the milestone birthday, Sophia caught the coronavirus. At first, she just had a fever, but on July 25, after four quiet days convalescing at home, her ribs began to hurt. The next day, Villarraga took her to the emergency room, where chest X-rays revealed that Sophia had developed pneumonia. She soon began coughing up blood.

Sophia was promptly admitted to Nicklaus Children’s Hospital, in Miami. Her parents, and their friends, were in shock. “I didn’t think that kids could get that sick,” Villarraga said.

But Sophia was one of roughly 130 children with COVID-19 who were admitted to a U.S. hospital that day, according to the Centers for Disease Control and Prevention. That number has been climbing since early July. From July 31 to Aug. 6, 216 children with COVID were being hospitalized every day, on average, nearly matching the 217 daily admissions during the pandemic’s peak in early January.

Hospitals in coronavirus hot spots have been particularly hard hit. On a single day last week, Arkansas Children’s Hospital, in Little Rock, had 19 hospitalized children with COVID; Johns Hopkins All Children’s Hospital, in St. Petersburg, Florida, had 15; and Children’s Mercy Kansas City, in Missouri, had 12. All had multiple children in the intensive care unit.

These numbers have sparked concerns that what had once seemed like the smallest of silver linings — that COVID-19 mostly spared children — might be changing. Some doctors on the front lines say they are seeing more critically ill children than they have at any previous point of the pandemic and that the highly contagious delta variant is likely to blame.

“Everybody is a little bit nervous about the possibility that the delta variant could in fact be, in some way, more dangerous in kids,” said Dr. Richard Malley, a pediatric infectious disease specialist at Boston Children’s Hospital.

Most children with COVID-19 have mild symptoms, and there is not yet enough evidence to conclude that delta causes more severe disease in children than other variants do, scientists said.

What is clear is that a confluence of factors — including delta’s contagiousness and the fact that people under 12 are not yet eligible to be vaccinated — is sending more children to the hospital, especially in areas of the country where the virus is surging.

“If you have more cases, then at some point, of course it trickles down to children,” Malley said.

Climbing cases

Many children’s hospitals had been hoping for a quiet summer. Several run-of-the-mill childhood viruses are less common during the warmer months, and national COVID rates had been declining through the spring.

But last month, as delta spread, that began to change.

“The number of positive COVID tests started to climb in early July,” said Marcy Doderer, president and CEO of Arkansas Children’s Hospital. “And then that’s when we really started to see the kids get sick.”

The vaccines are effective against delta — and provide powerful protection against severe disease and death — but children under 12 are not yet eligible for them. So as more and more adults get vaccinated, children make up an increasing share of COVID cases; between July 22 and July 29, they accounted for 19% of reported new cases, according to the American Academy of Pediatrics.

“They’re the unvaccinated,” said Dr. Yvonne Maldonado, a pediatric infectious-disease specialist at Stanford Medicine and chair of the AAP Committee on Infectious Diseases. “That’s where we’re seeing all the new infections.”

From July 22-29, nearly 72,000 new pediatric COVID cases were reported, almost twice as many as in the previous week, according to the association. At Johns Hopkins All Children’s Hospital, 181 children tested positive for the virus in July, up from just 12 in June.

Most of those children have relatively mild symptoms, such as runny noses, congestion, coughs or fevers, said Dr. Wassam Rahman, the medical director of the pediatric emergency center at All Children’s. “Most of the kids are not very sick,” he said. “Most will go home and be treated with preventive care at home. But as you might imagine, families are scared.”

A small share of children do develop severe disease, showing up at the hospital with pneumonia or in respiratory distress.

Of the 15 children with COVID-19 who were inpatients at Children’s Hospital New Orleans late last week, four — including a 3-month-old baby — were in intensive care, said Dr. Mark Kline, the hospital’s physician in chief. None of the children, including the eight who were old enough to be eligible, had been vaccinated.

“This delta variant of COVID-19 is an infectious disease specialist’s worst nightmare,” Kline said. “And there’s just no sign that it has started to plateau.”