RecruitingPhase 2Drug trialStudy of Tenofovir Alafenamide (TAF) in Children and Teen Participants With Chronic Hepatitis B Virus InfectionThe goals of this clinical study are to compare the effectiveness, safety and tolerability of study drug, tenofovir alafenamide (TAF), versus placebo in teens and children with CHB and to learn more about the dosing levels in children.