The Delta Variant Is Sending More Children to the Hospital. Are They Sicker, Too?

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,” Dr. 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, the president and chief executive 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 percent 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 A.A.P. Committee on Infectious Diseases. “That’s where we’re seeing all the new infections.”

From July 22 to July 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.”