The ACTIV3 study is testing if monoclonal antibody treatments -- laboratory-made proteins that mimic the immune system’s abilities -- improve recovery from patients hospitalized due to COVID-19.

The ACTIV4A Inpatient study is testing if treatments that aim to prevent blood vessel injuries and blood clots improve recovery from patients hospitalized due to COVID-19.

The C4R observational study is collecting participant data and samples to better understand COVID-19 and the associated symptoms and side effects.

The C3PO study is testing if convalescent plasma -- the liquid portion of blood collected from patients who have recovered from COVID-19 – prevents mild infection, being treated at home, from worsening and requiring hospitalization.

The ACTIV4B Outpatient study is testing if anticoagulation agents – blood thinners -- prevent mild infection, being treated at home, from worsening and requiring hospitalization.

The ACTIV4c Post-Discharge study is testing if anticoagulation agents – blood thinners – improve recovery from COVID-19 for individuals after being discharged from the hospital.