As the delta variant continues to spread, physicians are growing increasingly concerned about the rising number of pediatric Covid-19 hospitalizations—but the American Academy of Pediatrics is warning against "off-label" use of Pfizer-BioNTech's vaccine in children.

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A rise in pediatric hospitalizations

According to the Wall Street Journal, hospitals around the country, particularly in the South and Midwest, are reporting rising numbers of children being hospitalized for Covid-19. And although children are much less likely to be hospitalized or die due to Covid-19, HHS data shows that pediatric hospitalizations are now at the highest point since the agency started collecting data last year.

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For instance, Children's Hospital New Orleans has had as many as 20 children hospitalized for Covid-19 in the past three weeks, according to the hospital's physician-in-chief Mark Kline. In 2020, the most Covid-19 cases the hospitals had at a time was seven, Kline said.

Although it is not clear if the delta variant leads to more severe cases in children, some physicians, including Kline, believe it does.

According to Kline, around half of the children currently hospitalized with Covid-19 at his hospital don't have any underlying conditions. In contrast, most of the children who were hospitalized with Covid-19 before the delta variant also had other health issues, such as asthma or diabetes, he said.

Le Bonheur Children's Hospital in Memphis is experiencing a similar situation, the Journal reports. Nick Hysmith, the medical director of infection prevention at Le Bonheur, said before the last few weeks, his hospital rarely had any Covid-19 patients. Now, there are consistently a handful of children hospitalized with Covid-19, including at least two in the pediatric ICU.

In addition, Hysmith echoed Kline's assessment that the delta variant affects children differently, noting that many of the Covid-19 patients at his hospital don't have underlying conditions.

"This is different than we saw before. We weren’t sustaining those numbers several months ago," he said.

Children's hospitals are now preparing for even worse surges, particularly as schools reopen around the country, the Journal reports. Many hospitals are hiring more nurses, speeding up how rooms are cleaned, and creating contingency plans to expand capacity as needed. In addition, hospitals are preparing their staff for an increase in cases of multisystem inflammatory syndrome (MIS-C), a rare but potentially severe condition that can occur weeks after a Covid-19 infection.

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Pediatricians warn against off-label vaccine use

FDA on Monday fully approved Pfizer-BioNTech's Covid-19 vaccine, now labeled as Comirnaty, for individuals ages 16 and older—meaning that physicians can legally administer the vaccine "off-label" to children under 12 if they wish, STAT News' "Morning Rounds" reports.

However, the American Academy of Pediatrics (APP), acting FDA commissioner Janet Woodcock, and other public health experts are warning against off-label use of the vaccine in younger children, MedPage Today reports. In particular, experts have noted that doses being studied in younger children are lower than those used in adults and that no data about the effects of the vaccine in children under 12 has been published.

AAP on Monday issued a statement against off-label use of the vaccine in children under 12 and expressly warned physicians not to administer lower doses of the vaccine.

"We do not want individual physicians to be calculating doses and dosing schedules one-by-one for younger children based on the experience with the vaccine in older patients," Yvonne Maldonado, chair of AAP's committee on infectious diseases, said. "We should do this based on all of the evidence for each age group, and for that we need the trials to be completed."

AAP's president Lee Savio Beers also encouraged everyone who is eligible to be vaccinated to protect younger children who cannot receive a shot. "That will help reduce the spread of the virus and protect those who are too young to be vaccinated," Beers said.

Similarly, during a press conference on Monday, Woodcock also warned against off-label use of Pfizer-BioNTech's vaccine in younger children.

"We do not have data on proper dose, nor do we have full data on safety in children younger than what is in the [emergency use authorization], so that would be a great concern that people would vaccinate children," she said. "So we believe we need to get the ... data on usage in younger children. They are not just small adults; we have learned that time and time again."

Specifically, according to David Kimberlin, a pediatric infectious disease expert at the University of Alabama at Birmingham, the dose authorized for those 12 and older is 30 mcg, while the dose being evaluated for children ages 5 to 11 is "a third of that" at 10 mcg. And for children under 5, the dose is even lower, at 3 mcg.

"We can't have physicians writing for the approved 30 mcg dose to be used in someone under 12," Kimberlin said. "It's a much higher dose than what's being studied." (Toy/Wernau, Wall Street Journal, 8/22; Cooney, "Morning Rounds," STAT News, 8/24; Fiore, MedPage Today, 8/23)