Schools are reopening, even as the pandemic continues to brew in New York City. New cases are plateauing around 4,000 per day, as the variants start to take hold.

Kids are much less likely to catch the virus, but some who do can face serious consequences in the form of Multisystem Inflammatory Syndrome in Children, or MIS-C. It’s a condition where different body organs can become inflamed, including the heart, lungs, brain, and skin.

Now a study from Northwell Health, the state’s largest health system, spots a worrying outcome for COVID-positive children and their kidneys. The researchers looked through the medical records of 152 pediatric patients with COVID-19, admitted from March to August at four New York-area hospitals. About one out of 10 kids with COVID-19 had acute kidney injuries. The proportion doubled for those who also developed MIS-C. Severe kidney dysfunction in children is typically very rare—on the order of one to two dozen cases per 100,000 children in developed countries.

Christine Sethna is an associate professor at Northwell’s Feinstein Institutes for Medical Research and one of the study’s co-authors. She spoke with WNYC’s David Furst about their findings, how parents can spot MIS-C, and when kids might be eligible for COVID-19 vaccines.