“There’s no firm evidence that the disease is more severe,” said Dr. Jim Versalovic, the pathologist in chief and interim pediatrician in chief at Texas Children’s Hospital, in Houston, where about 10 percent of children now test positive for the virus, up from less than 3 percent in June. “We certainly are seeing severe cases, but we’ve seen severe cases throughout the pandemic.”…

But in the U.K., where Delta swept through the population before the variant became widespread in the United States, experts say they have not seen clear evidence that the variant is making children sicker.

“There was a wave, there were children who became unwell,” said Dr. Elizabeth Whittaker, a pediatric infectious disease and immunology specialist at Imperial College London. “But not in the kind of, ‘Oh, my gosh, this is very different, this is worrying.’”