Effect of SARS-CoV-2 IgG Seroconversion After Convalescent Plasma Transfusion on Hospital Outcomes in COVID-19

Background

Convalescent plasma increases SARS-CoV-2 clearance in COVID-19, especially in patients lacking preexisting antibodies.

Research Question

In hospitalized patients with COVID-19 receiving convalescent plasma, does conversion to a positive SARS-CoV-2 IgG status provide mortality benefit in patients who lacked SARS-CoV-2 IgG?

Study Design and Methods

This observational study included consecutive hospitalized patients with COVID-19 who received convalescent plasma under the Expanded Access Program from April through August 2020. SARS-CoV-2 N-based IgG antibody enzyme-linked immunosorbent assay measurements before and after transfusion were recorded. Outcomes of patients without preexisting antibodies who demonstrated seroconversion immediately after receipt of convalescent plasma were compared with those who did not show seroconversion. Hospital mortality was the primary outcome.

Results

Two hundred seventy-five hospitalized patients received convalescent plasma during the study period. SARS-CoV-2 IgG was collected from 234 patients. One hundred ten patients (47%) showed seropositive findings and 124 patients (53%) showed seronegative findings before transfusion. Among the seronegative group, 63 patients (50.8%) demonstrated seroconversion after plasma transfusion, whereas 61 patients (49.2%) continued to show seronegative findings despite transfusion. Age, sex, BMI, Sequential Organ Failure Assessment score, and receipt of high-titer plasma were similar across all subgroups. Seroconversion after transfusion was not associated with survival at hospital discharge (OR, 1.9; 95% CI, 0.7-4.9; P = .17).

Interpretation

Serologic response after transfusion of convalescent plasma was not shown to be associated with hospital survival in patients with COVID-19 without preexisting SARS-CoV2 IgG antibodies.