Lexie Stroiney, 6, curls up in the plethysmography chamber during a break in her pulmonary function test at Children's National Hospital in Washington on Jan. 26, 2022. Lexie had COVID-19 and is part of a NIH-funded multi-year study to look at impacts of COVID-19 on children's physical health and quality of life. (AP Photo/Carolyn Kaster)