Omicron is a 'different beast' in kids, but it doesn't seem more dangerous, disease experts say

• The US recorded nearly 1 million child COVID-19 cases last week — its highest-ever weekly count.
• Omicron has made pediatric cases more prevalent, but it doesn't appear to be more virulent in kids.

More US children got COVID-19 last week than in any other week of the pandemic.

The US recorded more than 981,000 child COVID-19 cases from January 7 to January 13, according to a Tuesday report from the American Academy of Pediatrics (AAP). That's a nearly 70% increase from the week prior, and triple the number of child COVID-19 cases recorded in the last week of December. Since states report kids' health data differently, age ranges vary, but the data generally include kids from birth up to age 17-20.

Disease experts attribute the pediatric surge to the Omicron variant, which drove COVID-19 cases among all age groups to record highs this month: The US recorded more than 1.4 million new cases on January 10, its highest-ever daily count. A combination of school outbreaks and low pediatric vaccination rates — including among kids who are vaccine-eligible — may also be facilitating the virus' spread in young people.

Vaccines still protect children from hospitalization and death, experts said, but Omicron may result in a unique set of symptoms among kids.

"The virus is a different beast right now in terms of the clinical manifestations that we're seeing in children," Dr. Erlinda Ulloa, a pediatric infectious disease specialist at the University of California, Irvine, told Insider.

Ulloa said children with COVID-19 at her hospital are reporting more overall symptoms than they were with the Alpha and Delta variants. She's also seeing more instances of croup and bronchiolitis — infections commonly associated with respiratory viruses — among unvaccinated kids under age 5.

The virus is "changing its presentation," Dr. Sunanda Gaur, a pediatric infectious disease specialist at Rutgers Robert Wood Johnson Medical School, told Insider. "But we can't say that Omicron is more severe in unvaccinated [people] if we compare it to, let's say, Delta."

Most kids still have mild symptoms, but croup and bronchiolitis are becoming more common

Since the pandemic started, children have represented around 18% of total COVID-19 cases in the US, according to the AAP report. But children made up 21% of reported weekly COVID-19 cases between January 7 and January 13.

As more kids get infected, the number of pediatric hospitalizations has also gone up. A month ago, around 300 children under age 18 were hospitalized with COVID-19 in the US. As of Tuesday, the number of hospitalized children with COVID-19 had risen to 930, according to data from the US Department of Health and Human Services.

"Most kids that are admitted just happen to be PCR-positive and admitted for another reason — maybe 20-30% are admitted for acute COVID," Dr. Jennifer Lighter, an associate professor of pediatric infectious diseases at NYU School of Medicine, told Insider.

Among children who got COVID-19, 0.02% or fewer died from the disease as of January 13, the AAP report found.

"For the most part, children have milder symptoms than adults," Gaur said. "Typically, if they're otherwise healthy and don't have any underlying conditions such as obesity or diabetes or asthma, any sort of congenital disorders, they don't get many complications."

Gaur said she would classify both croup and bronchiolitis as mild symptoms. But some doctors aren't sure if COVID-19 is the root cause of these respiratory infections.

"Some of these kids are probably dually infected with other viruses that typically cause croup and bronchiolitis at this time of the year. So it's really hard to untangle the impact of COVID specifically on those diagnoses," Dr. Mark Sawyer, an infectious disease specialist at Rady Children's Hospital in San Diego, told Insider.

The rapid spike in child COVID-19 cases also makes it likely that doctors will encounter a wider array of symptoms, he added.

"We're sort of dwarfed by the overall numbers," Sawyer said. "More and more kids are coming in of all descriptions."

Doctors still worry about kids under 5 who aren't vaccine-eligible

Disease experts said their vaccinated patients are faring much better than unvaccinated ones.

"The kids that are fully vaccinated do not end up in the hospital," Ulloa said, adding, "I don't have any child that's in the ICU that's vaccinated."

But they worry about severe outcomes in kids under 5, who aren't eligible for vaccines yet. Some of these kids also attend school or daycare in person, where they face a high risk of exposure to the virus.

Vaccines for little ones could still be several months away. Pfizer, which is studying two ultra-low doses of its vaccine among kids ages 2-5 in clinical trials, recently found that its 3-microgram dosage didn't offer enough protection for that age group. In comparison, kids ages 5-11 receive 10 micrograms per dose, and adults get 30 micrograms. In a statement last month, Pfizer said it was considering adding a third dose to the regimen for babies and toddlers.

Experts also worry about low vaccination rates among kids overall. Just 19% of kids ages 5-11 have had two vaccine doses as of Wednesday, according to data from the Centers for Disease Control and Prevention.

"I don't want any child getting severe disease, but also I just want kids' lives back to normal," Lighter said. "Kids should be in schools. Kids should be back to having an active life. They shouldn't have to be isolating because of exposures in the classroom."