The ACTIV4 Host Tissue platform is testing if treatments targeting the host-tissue response to SARS-CoV-2 infection can improve recovery and prevent worsening in patients hospitalized with COVID-19.

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 ACTIV3b study is testing if treatments improve recovery from patients hospitalized due to COVID-19.

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.

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