The largest published COVID-19 pediatric series to date included only 13 patients considered to be critically ill and only described the Chinese outbreak. There are essentially no data outside of this and nothing to begin to understand the prevalence of severe/critical pediatric COVID-19, the risk factors associated with this illness, outcomes from COVID-19, and factors (patient or treatment) that may be associated with an improved or worsened outcome. This study will identify all children admitted to an inpatient unit with a diagnosis of COVID-19. Clinical data will be collected through medical record review to describe in detail the demographics and clinical characteristics, including clinical course and treatment, of infected children who require hospitalization.

This will be a 26-week, prospective, multicenter, randomized, double-blind, placebo-controlled safety and efficacy study of udenafil 87.5 mg tablets versus placebo (both taken twice daily in adolescent subjects who have had the Fontan procedure. The primary efficacy endpoint will be change from baseline at 26 weeks in peak minute oxygen consumption [VO2] (mL/kg/min).