The Role of Disease Severity and Demographics in the Clinical Course of COVID-19 Patients Treated With Convalescent Plasma

Abstract

Treatment of patients with COVID-19 using convalescent plasma from recently recovered patients has been shown to be safe, but the time course of change in clinical status following plasma transfusion in relation to baseline disease severity has not yet been described. We analyzed short, descriptive daily reports of patient status in 7,180 hospitalized recipients of COVID-19 convalescent plasma in the Mayo Clinic Expanded Access Program. We assessed, from the day following transfusion, whether the patient was categorized by his or her physician as better, worse or unchanged compared to the day before, and whether, on the reporting day, the patient received mechanical ventilation, was in the ICU, had died or had been discharged. Most patients improved following transfusion, but clinical improvement was most notable in mild to moderately ill patients. Patients classified as severely ill upon enrollment improved, but not as rapidly, while patients classified as critically ill/end-stage and patients on ventilators showed worsening of disease status even after treatment with convalescent plasma. Patients age 80 and over showed little or no clinical improvement following transfusion. Clinical status at the time of convalescent plasma treatment and age appear to be the primary factors in determining the therapeutic effectiveness of COVID-19 convalescent plasma among hospitalized patients.

Keywords: COVID-19; SARS-CoV-2; antibodies; antibody therapy; convalescent plasma therapy.

Figure 1

Trajectories of daily status improvement/worsening. Subgroup analyses include (A) all patients, (B) by age, (C) by sex, (D) by initial clinical status, (E) by ICU status prior to transfusion, and (F) by ventilator status prior to transfusion. Net patient scores of 0 = no net change, +1 = net improvement but still hospitalized, −1 = net worsened and still hospitalized, +2 = discharged from hospital, and −2 = patient expiration. Points are the mean score for each day, and gray bands indicate the 95% confidence interval for each data set.