The authors reply: Although the clinical data regarding convalescent plasma can be complex to interpret, we concur with Joyner and Pirofski that some randomized clinical trials have shown that transfusions containing high levels of SARS-CoV-2 antibodies (monoclonal or polyclonal) that were administered to outpatients with early-stage Covid-19 reduced the incidence of hospitalization by 50 to 80%. In addition, polyclonal-antibody preparations should be less susceptible to viral escape than monoclonal antibodies.1