The current delta-fueled COVID-19 surge is sending more children to hospitals locally and across the nation, a sign, doctors said, that adults need to do a better job of protecting kids, especially those under 12 who cannot get vaccinated.

Nationally, child hospitalizations for COVID-19 increased 84% between July 10 and July 31, from 665 to 1,224, according to the U.S. Department of Health and Human Services. In this region, the number of pediatric hospitalizations rose from four to 13 in New Jersey and from 20 to 28 in Pennsylvania between July 10 and July 31. Though rising, the hospitalization rates remain low; 1.1 per 100,000 children in Pennsylvania and 0.7 per 100,000 in New Jersey.

According to a report from the American Academy of Pediatrics (AAP) and the Children’s Hospital Association, only 0.1% to 1.9% of all known cases in children lead to hospitalization. The true percentage is likely even lower because many infected children are not tested, said Sara Bode, who is director of school health services at Nationwide Children’s Hospital in Columbus, Ohio, and chair of an AAP committee on school health.

Yet the trend is concerning to experts.

Bode said hospitalizations of children typically rise in concert with those of adults in their community. Over the last two weeks, she said, both the number of children testing positive and those needing hospitalization have doubled at her hospital. While the numbers remain small, “that’s a significant trend that we need to be paying attention to,” she said. She worries the situation will worsen in the fall when children go back to school, people spend more time inside, and the virus spreads more easily.

The AAP report said the number of children testing positive for COVID-19 rose from its summer low point of 8,447 on June 24 to 71,726 on July 29. At the peak of the winter surge in mid-January, there were more than 211,000 cases in children.

The report said that 358 children have died of COVID-19, including two in Delaware, seven in New Jersey, and 15 in Pennsylvania. Pennsylvania includes everyone up to age 19 in its child case data, while New Jersey goes to age 17.

A study from the United Kingdom published in Lancet Child and Adolescent Health this week said the average illness among children lasted six days, and 98% recovered fully within eight weeks. However, 4.4% had symptoms — fatigue was the most common — that lasted longer than a month. Those ages 12 and up tended to have more symptoms and a slightly longer course than younger kids.

Bode said most children hospitalized with COVID-19 need only a few days in the hospital, but some have been sick enough to require a stay in the intensive care unit.

Doctors at St. Christopher’s Hospital for Children in Philadelphia and UPMC Children’s Hospital in Pittsburgh both said more children are testing positive and needing hospital care. The number with COVID-19 rose from four on June 20 to 10 on July 25 at St. Chris. The numbers are still in single digits at UPMC, but the test positivity rate in outpatient settings increased dramatically in the last week, from 1.9% to 7%, said John Williams, chief of the division of pediatric infectious diseases. That is a sign of community spread.

Jonathan Miller, chief of primary care for Nemours duPont Hospital for Children in Wilmington, said his hospital had only two patients who had tested positive for COVID-19 Wednesday morning, and neither was admitted because of the virus. He said his area so far also has not seen an increase in cases. In July, 20 children tested positive, the least since May 2020. The peak was January 2021 with 91 positive tests.

Williams said he is concerned because kids under 12 cannot yet receive vaccines, the delta variant is spreading rapidly, and many people have been taking fewer precautions.

“The only thing protecting these young kids is the rest of us and, as a country, we’re doing a poor job of protecting these young kids right now,” he said. He said vaccination rates need to rise among older kids and adults, and everyone, regardless of vaccine status, needs to wear masks more often.

Pediatricians locally and nationally are also seeing an increase in other respiratory viruses that gave us a break while we were staying home, social distancing, and masking. The most serious of these are respiratory syncytial virus (RSV) and parainfluenza. Doctors said the common cold managed to keep spreading throughout the pandemic. RSV and parainfluenza usually strike in fall and winter but are making a strong early appearance. At St. Christopher’s, 76 children tested positive for RSV in June and 110 in July. “It’s definitely an abnormal summer,” said Emily Souder, an infectious-diseases doctor there.

So far, doctors have seen no evidence that delta is making kids sicker than previous versions of the virus did or causing different symptoms. Whether they can spread it more easily is unknown. Some children who needed hospitalization for COVID-19 in general have had underlying health problems, but many were healthy before they developed breathing problems or pneumonia. Some children infected with the virus can also develop MIS-C, or multisystem inflammatory syndrome, a potentially serious condition. Souder said St. Christopher’s has seen more than 30 children with MIS-C during the pandemic.

Doctors say that the best way for parents to protect their kids is to be vaccinated themselves, vaccinate eligible older children, socialize with other vaccinated people, and wear masks in public places. Souder says it’s better to eat outside than inside with kids at restaurants.

The AAP recommends that everyone wear masks inside schools. Souder thinks it’s better for children to return to in-person learning, and she wants it to work. Mitigation efforts like masking worked last year. “It was not the kids who had trouble with that,” she said.

She called it a “real travesty” that some adults are fighting steps that would protect kids, vulnerable adult staff, classmates with health problems, and poorly vaccinated communities. “It’s really the adults’ responsibility to continue promoting that, to model for your own children the use of these strategies,” she said.

If schools start without widespread masking, Bode said, “the consequence of that is we’re going to be back to virtual learning.” Her own children are vaccinated, and she would still recommend they mask in school to make that “normative” for all kids.

Asked what kind of masks kids should wear, Bode said “one that they’re going to keep on.” Miller said that children’s masks with adjustable ear loops are “really useful.”

It’s too soon to know whether masks and distancing will work as well with delta. “I think we have to be mindful of that,” Bode said. “We have to follow the data.”

Miller says the virus should have taught us to be cautious by now. “It’s probably worth being a little bit more conservative than you think you need to be,” he said, ”because we as a society keep getting burnt.”