The FDA has given EUA (Emergency Use Authorization) for bamlanivimab (Lilly) or the “cocktail” of casirivimab and imdevimab IV infusions for mild to moderate COVID-19 patients. These monoclonal antibodies block the binding of the spike protein to the ACE2 receptor on the human cell, which blocks viral attachment. If given early (within 10 days of symptom onset), both medicines have been shown in high-risk adults to reduce the viral load and risk of progression to severe COVID-19, and reduce the necessity for ED visits and hospitalization. However, they didn’t help those already hospitalized and outcomes were worse in those receiving high-flow oxygen or mechanical ventilation. Experts suspect that infusions given within the first 3 days of symptoms will be more effective than when given later. This is similar to what we have experienced with the use of oseltamivir (Tamiflu) in Influenza or antivirals with shingles.