RecruitingPhase 3Drug trialLow Dose Sirolimus in People With Post-Acute Sequelae of COVID-19 (PASC) Long COVID-19The study is conducted in New York, New York at The Cohen Center for Recovery from Complex Chronic Illness at Mount Sinai. This is an IND-exempt, off-label, multi-ascending, randomized, placebo-controlled clinical trial of sirolimus (also known as rapamycin) in adults with Long COVID. There are 2 arms: Sirolimus and Placebo. This study aims to evaluate the efficacy of Sirolimus in adults with Long COVID. Efficacy will be evaluated by measuring patient-reported outcomes in response to Sirolimus.