RecruitingPhase 2Drug trialMitoquinone/Mitoquinol Mesylate as Oral and Safe Postexposure Prophylaxis for Covid-19Adults who do not have major health, kidney, gastrointestinal disease will be randomized to receive oral mitoquinone/mitoquinol mesylate (Mito-MES) versus placebo to prevent the development and progression of COVID-19 after high-risk exposure to a person with confirmed SARS-CoV-2 infection.