6  OUTSTANDING questions
1. Define the molecular basis for mononuclear phagocyte contributions to different stages of COVID-19 resistance and pathogenesis.
2. Define interactions between mononuclear phagocytes, COVID-19 and other host cells in different tissues.
3. Develop tests to quantify biomarkers of monocytes and tissue macrophages during COVID-19, for diagnosis, prognosis, therapy and prevention.