A study in the New England Journal of Medicine (NEJM) this week shows that Eli Lilly's COVID-19 convalescent plasma–derived virus-neutralizing monoclonal antibody treatment (LY-CoV555) reduced viral loads, lowered the severity of symptoms, and had no serious adverse effects in outpatients.The data from a phase 2 trial confirm preliminary results in September from a smaller cohort of outpatients—those visiting clinics—with similar outcomes.Animal studies of neutralizing antibodies have shown promising results, with significant reductions in viral loads in the upper and lower respiratory tracts where SARS-CoV-2, the virus that causes COVID-19, is thought to bind and cause disease.