CP and COVID-19: However, a relationship between neutralizing antibody (NAb) titer and a more favorable clinical outcome have been suggested,9,13 and CP was associated with a decreased 28-day mortality rate when high titer plasma was used14 or when CP was administered early in the course of the disease.15 Data from available RCTs have several limitations, including the administration of plasma with low NAb titer, the use of suboptimal surrogate serological tests to determine NAb titer, and most importantly, the delayed administration of CP from the onset of COVID-19 symptoms.