This study looks at using arginine, a type of protein, to help kids with COVID-19. Arginine might help the mitochondria, the energy makers in our cells, work better. The study is at Children's Healthcare of Atlanta, Egleston campus. Kids will be randomly given one of three arginine doses, three times a day for up to five days or until they leave the hospital.

COVID-19 can be more serious for some kids, leading to problems like multisystem inflammatory syndrome (MIS-C) and "Long Covid." Research shows that low arginine levels might be linked to severe COVID-19. The study also explores other things like sPLA2, an enzyme that could predict how bad the disease might get. Learning more about these things could help find better treatments in the future.

To join, kids must be aged 3 to 21, hospitalized for COVID-19, but cannot join if they have things like severe liver or kidney issues, are pregnant, or have certain past medical histories.

• The study lasts 5 days or until discharge.
• Participants will receive arginine three times a day.
• Conducted at Children's Healthcare of Atlanta.